Bees: Mushrooms are theirs – and with them our food.

Bees, as we well know, are responsible for pollinating approximately 75% of the world's food crops, an ecological service that according to the FAO is worth about $235-577 billion annually globally. However, these tireless pollinators are facing unprecedented threats: pesticides, habitat loss, climate change, and pathogens are decimating colonies worldwide. It is in this critical scenario that mycology is revealing unexpected solutions.

Fungi, long considered in a separate category from the plant kingdom, are demonstrating extraordinary properties that can support bee health in ways we are only beginning to understand. From the antiviral and antibacterial properties of some species to the ability to detoxify the environment, fungi represent a biological resource of invaluable worth for addressing the pollinator crisis. In this article, we will explore every aspect of this relationship, providing detailed data, comparative tables, and practical information for mycoculturists, beekeepers, and all those interested in safeguarding biodiversity and food security.

Bees in crisis: dimensions of a global emergency

Before delving into the role of fungi in bee health, it is essential to understand the extent of the crisis these insects are facing. In recent decades, beekeepers and researchers worldwide have recorded unprecedented colony mortality rates, with losses in some regions exceeding 30-50% annually. This phenomenon, known as Colony Collapse Disorder (CCD), has multifactorial causes that we are only beginning to fully decipher.

Statistical data on bee decline

The numbers of bee decline speak for themselves and paint a worrying picture for the future of pollination and, consequently, global food production. According to the report by the IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services), over 40% of invertebrate pollinators, particularly bees and butterflies, face the risk of extinction. In Europe, studies indicate that 37% of bee populations are in decline, while 24% risk extinction.

The economic consequences of pollinator decline

The economic impact of decreasing bee populations is difficult to overstate. According to FAO estimates, of the 100 crop species that provide 90% of the world's food, 71 are pollinated by bees. Without these insects, the production of many fruits, vegetables, and nuts would drastically decrease, leading to price increases and potential food insecurity in many regions of the world. Some studies suggest that the complete loss of pollinators could reduce global fruit production by 23%, vegetables by 16%, and nuts and seeds by 22%.

The main threats to bee health

Bees face a lethal cocktail of threats that act in synergy, making it difficult to identify a single cause for their decline. Among the most significant factors are:

Pesticides and systemic insecticides: neonicotinoids, in particular, have been linked to sublethal effects on bees, impairing their navigation, learning, and reproduction abilities. Even when not directly lethal, these chemicals make bees more vulnerable to other threats.

Parasites and pathogens: the Varroa destructor mite represents one of the most serious threats to global beekeeping, acting as a vector for numerous viruses that weaken and kill colonies. Other pathogens like Nosema ceranae contribute to the overall stress of bees.

Habitat loss and fragmentation: intensive agriculture and urbanization have drastically reduced the availability of diverse floral resources, depriving bees of necessary nourishment and exposing them to a monotonous diet that compromises their immune system.

Climate change: the alteration of seasonal patterns and extreme weather events interferes with the synchronization between plant flowering and bee activity, creating critical food shortages at crucial times in their life cycle.

In this alarming context, the search for innovative and sustainable solutions becomes an absolute priority. It is here that fungi come into play with extraordinary potential that deserves to be explored in depth.

The world of fungi: an unexplored resource for bee health

The fungal kingdom represents one of the most promising frontiers in pharmacological and biotechnological research. With over 5 million estimated species (of which only about 150,000 are classified), fungi possess an extraordinary chemical and metabolic diversity that has evolved over millions of years of adaptation. Many compounds produced by fungi have demonstrated antibiotic, antiviral, anti-inflammatory, and immunomodulatory properties that are revolutionizing our understanding of natural medicine and health management.

Fungi with beneficial properties for pollinator insects

Among the thousands of studied fungal species, several have demonstrated properties particularly relevant to bee health. These fungi, through their secondary metabolites, can act on different fronts: strengthening the immune system, countering viral and bacterial pathogens, and even detoxifying the environment from harmful chemicals. Research in this field is still in its early stages, but preliminary results are extremely promising.

Ganoderma lucidum (Reishi) and its immunomodulatory properties

Ganoderma lucidum, known as Reishi, is one of the most studied medicinal fungi in the world. Its fame in traditional Chinese medicine dates back thousands of years, where it was considered the "mushroom of immortality." Modern science has validated many of its properties, identifying beta-glucans and triterpenes as the main compounds responsible for its beneficial effects. Recent studies have shown that Reishi extracts can significantly enhance the immune response in bees, increasing the production of antimicrobial peptides and improving their resistance to bacterial infections such as American and European foulbrood.

Fomes fomentarius and Its antiviral action

Fomes fomentarius, known as "tinder fungus" for its traditional use in fire-starting, is revealing surprising properties in the fight against viruses that plague bees. Research conducted at the University of Naples has identified compounds in this fungus capable of inhibiting the replication of Deformed Wing Virus (DWV), one of the most devastating pathogens associated with the Varroa mite. The integration of Fomes fomentarius extracts into bee feed showed a significant reduction in viral load and improved survival of infected colonies.

Hericium erinaceus (Lion's Mane) and gut health

Hericium erinaceus, known as Lion's Mane, is renowned for its regenerative effects on the nervous system and digestive tract. In humans, studies have demonstrated its ability to stimulate the production of nerve growth factor (NGF) and repair the gastric mucosa. In bees, extracts of this fungus appear to improve gut health, strengthening the epithelial barrier and positively modulating the microbiota, resulting in improved nutrient absorption and resistance to intestinal pathogens like Nosema ceranae.

Trametes versicolor (Turkey Tail) and detoxification

The Trametes versicolor, or Turkey Tail, is one of the most common fungi in forests worldwide. Research has focused attention on this fungus for its extraordinary ability to degrade complex organic compounds, including many environmental pollutants. Laboratory studies have shown that the mycelium of Trametes versicolor can metabolize a wide range of pesticides, including some neonicotinoids, transforming them into less toxic compounds. This property could be exploited to create safer environments for bees, reducing their exposure to harmful chemicals.

Mechanisms of action: how fungi protect bees

Understanding how compounds derived from fungi interact with bee physiology is fundamental to developing practical and effective applications. The mechanisms of action are multifactorial and involve different biological systems, from the immune system to metabolism, from detoxification to microbiota modulation. In this section, we will explore in detail the processes through which fungi exert their beneficial effects on bees, based on the most recent scientific evidence.

Immune system modulation

The immune system of bees, although less complex than that of vertebrates, is extraordinarily effective at protecting these insects from a wide range of pathogens. However, when subjected to multiple stresses, this system can be overwhelmed, leading to infections and colony collapse. Medicinal fungi, particularly through their beta-glucans, can enhance the innate immune defenses of bees in specific and measurable ways.

Activation of humoral immunity

Humoral immunity in bees relies on the production of antimicrobial peptides (AMPs) such as abaecin, defensin, and apidaecin. These molecules are capable of destroying a wide variety of pathogens by acting on their cell membranes. Studies conducted at the University of Helsinki have demonstrated that supplementation with medicinal mushroom extracts significantly increases the gene expression of these antimicrobial peptides, enhancing the bees' ability to counteract bacterial infections such as American foulbrood (caused by Paenibacillus larvae) and European foulbrood (caused by Melissococcus plutonius).

Enhancement of cellular immunity

Cellular immunity in bees primarily involves specialized hemocytes that phagocytize and destroy pathogens. The beta-glucans from fungi interact with specific receptors on the surface of these cells, activating signaling pathways that increase their phagocytic activity and the production of reactive oxygen species (ROS) with microbicidal activity. This mechanism is particularly important for countering fungal infections like those caused by Ascosphaera apis, the causative agent of chalkbrood.

Direct and indirect antiviral action

Viruses represent one of the greatest threats to bee health, often transmitted by the Varroa destructor mite which acts as a vector. While antibiotics are ineffective against viruses, various compounds derived from fungi have demonstrated antiviral activity through both direct and indirect mechanisms.

Inhibition of viral replication

Some triterpenes isolated from Ganoderma lucidum and polysaccharides from Fomes fomentarius have shown the ability to interfere with key stages of the replication cycle of viruses such as Deformed Wing Virus (DWV) and Acute Bee Paralysis Virus (ABPV). These compounds appear to inhibit virus entry into host cells or interfere with the transcription of viral genetic material, significantly reducing viral load in infected bees.

Stimulation of RNA interference

Bees, like many other insects, possess an antiviral defense system based on RNA interference (RNAi), which recognizes and degrades viral RNA. Some studies suggest that fungal compounds may enhance this natural defense system, increasing the expression of key components of the RNAi pathway such as Dicer-2 and Argonaute-2. This indirect mechanism could explain the effectiveness of some fungal extracts against a wide range of viruses, even when they show no direct antiviral activity in vitro.

Protection against oxidative stress

Oxidative stress, caused by an imbalance between the production of reactive oxygen species (ROS) and the antioxidant capacity of cells, is implicated in many bee pathologies and premature aging. Pesticides, pathogens, and other environmental stressors can increase ROS production, damaging lipids, proteins, and cellular DNA.

Antioxidant activity of fungal compounds

Many fungi contain potent antioxidants such as phenols, flavonoids, ergothioneine, and melanins that can neutralize ROS and protect cells from oxidative damage. Ergothioneine, in particular, is a unique antioxidant that fungi accumulate in high concentrations and has been shown to protect cells from oxidative stress more effectively than many conventional antioxidants. Supplementation with fungi rich in these compounds could help bees counteract oxidative stress induced by pesticides and other environmental factors, preserving cellular function and prolonging longevity.

Modulation of the gut microbiota

The gut microbiota of bees plays a crucial role in their health, influencing digestion, the synthesis of essential nutrients, and resistance to pathogens. Imbalances in this microbial ecosystem (dysbiosis) are associated with various pathologies and increased susceptibility to infections.

Prebiotic effects of beta-glucans

The beta-glucans from fungi, in addition to their immunomodulatory effects, can act as prebiotics, promoting the growth of beneficial bacteria in the bee gut. Studies have shown that supplementation with beta-glucans increases the abundance of Lactobacillus and Bifidobacterium, bacterial genera associated with better gut health and greater resistance to pathogens like Nosema ceranae. This prebiotic effect could be particularly important in contexts of monofloral feeding or scarcity of diverse nectar resources.

Practical applications: integrating fungi into beekeeping

Transferring scientific knowledge about the relationship between fungi and bees into practical applications for beekeepers represents the most important phase of this research path. In this section, we will explore the different ways in which fungi can be integrated into beekeeping management, from dietary supplementation protocols to environmental enrichment strategies, providing concrete indications based on available evidence and the experiences of pioneering beekeepers in this field.

Preparation of mushroom-based dietary supplements

Dietary supplementation represents the most direct method for administering beneficial compounds derived from fungi to bees. However, preparing these supplements requires care to ensure efficacy, safety, and stability over time. There are several possible formulations, each with specific advantages and limitations.

Sugar syrups supplemented with fungal extracts

Sugar syrups (typically prepared with a 1:1 or 2:1 ratio of sugar to water) are the most common vehicle for dietary supplementation in beekeeping. The addition of mushroom extracts to these syrups represents a simple and effective method for administering beneficial compounds to bees. The optimal preparation involves using standardized aqueous or hydroalcoholic extracts, added to the cooled syrup to avoid thermal degradation of the active compounds. Effective concentrations vary depending on the fungal species and extract used but generally range between 0.5% and 2% of the total syrup volume.

Protein pastes enriched with mycelium

Protein pastes, used to supplement the diet of bees during periods of pollen scarcity, can be enriched with dried and ground mycelium of fungi. This formulation is particularly suitable for fungi like Hericium erinaceus that show beneficial effects on gut health. The mycelium, cultivated on sterile substrates and then dried at low temperatures, retains most of the active compounds and can be mixed with other protein ingredients such as soy flour, brewer's yeast, and pollen powder.

Medicated candy with mushroom powders

Candy, prepared with powdered sugar and honey, represents another supplementation method particularly useful during winter when bees do not take liquid syrups. The addition of dried mushroom powders (preferably extracts and not the whole mushroom for better bioavailability) to these preparations allows for prolonged administration of beneficial compounds. This formulation is ideal for fungi like Ganoderma lucidum that require continuous intake to exert their immunomodulatory effects.

Administration protocols: timing and dosages

The effectiveness of mushroom-based supplements depends not only on the formulation but also on the timing and dosages of administration. Suboptimal protocols can significantly reduce benefits or, in extreme cases, be counterproductive. Based on available evidence and practical experiences, general guidelines for fungal supplementation in beekeeping can be outlined.

Safety considerations

Before implementing any fungal supplementation protocol, it is essential to consider safety aspects. Although the species mentioned in this article are generally considered safe, it is important to use only fungi from reliable sources, cultivated under controlled conditions, and correctly identified. Wild-harvested fungi might contain environmental contaminants or be confused with toxic species. Furthermore, it is always advisable to start with small test batches to evaluate acceptance by the bees and monitor any adverse effects before extending the treatment to the entire apiary.

Environmental enrichment with fungi

In addition to direct dietary supplementation, the benefits of fungi can be harnessed through environmental enrichment strategies that aim to create ecosystems more favorable to bee health. These approaches, although less studied, offer the advantage of being more sustainable and naturally integrating into the biology of bees and their environment.

Installation of "mycelial gardens"

"Mycelial gardens" involve the creation of specific areas within or near apiaries where beneficial fungal species are inoculated. These areas, properly prepared with suitable substrates (such as decaying wood for wood-decaying fungi or straw beds for terrestrial fungi), allow the development of mycelial networks that can improve the surrounding ecosystem in several ways: detoxifying soil and water, improving the health of nectar-bearing plants, and potentially releasing beneficial volatile compounds into the environment.

Use of mycofilters

Mycofilters are systems that use fungal mycelium to filter and purify water before it is available to bees. This technology, already used in environmental remediation contexts, exploits the ability of fungi like Trametes versicolor to degrade organic contaminants. Placing water tanks equipped with mycofilters near apiaries can reduce bee exposure to pesticides and other pollutants present in natural water sources.

Research and scientific studies: evidence and future perspectives

The relationship between fungi and bees is a relatively new but rapidly evolving field of research, with studies producing increasingly solid evidence supporting the use of fungi in beekeeping. In this section, we will examine in detail the most significant research conducted to date, analyze their results, and discuss future research directions, identifying the knowledge gaps still to be filled and the potential applications that could emerge in the coming years.

Key studies and their results

Over the last ten years, several research groups worldwide have begun to systematically investigate the effects of fungi on bee health. These studies, although conducted with different approaches and methodologies, converge in demonstrating the potential of fungi as sustainable tools for managing bee health.

University of washington research on Ganoderma lucidum

A pioneering study conducted at the University of Washington and published in the journal Scientific Reports in 2018 investigated the effects of Ganoderma lucidum extracts on the bee immune system. Researchers administered aqueous extracts of Reishi to groups of bees in laboratory conditions, subsequently measuring the expression of immune genes and resistance to bacterial infections. The results showed a significant increase in the expression of antimicrobial peptides such as abaecin and defensin, as well as greater survival of bees exposed to Paenibacillus larvae, the causative agent of American foulbrood.

Italian study on Fomes fomentarius and bee viruses

An Italian research group, in collaboration between the University of Bologna and the Experimental Zooprophylactic Institute of the Venezie, published a study in 2020 on the efficacy of Fomes fomentarius against Deformed Wing Virus (DWV). The research, conducted both in vitro and in vivo, demonstrated that a specific polysaccharide isolated from this fungus is able to inhibit DWV replication, reducing the viral load in infected bees by 45-60% compared to the control group. This effect was accompanied by a significant reduction in clinical symptoms associated with the virus, such as deformed wings and reduced abdomens.

Swedish research on Trametes versicolor and detoxification

Researchers from Uppsala University in Sweden investigated the ability of Trametes versicolor mycelium to degrade neonicotinoid pesticides under simulated field conditions. The study, published in 2021 in the journal Environmental Science and Technology, demonstrated that the mycelium of this fungus can degrade up to 80% of imidacloprid and clothianidin present in aqueous solutions over a 72-hour period. Subsequent toxicity tests confirmed that the degradation products were significantly less toxic to bees than the original compounds.

Canadian study on Hericium erinaceus and gut microbiota

A research team from the University of British Columbia examined the effects of Hericium erinaceus supplementation on the gut microbiota of bees and resistance to Nosema ceranae. The results, published in 2022 in the journal Apidologie, showed that bees supplemented with Lion's Mane extracts had a lower Nosema load and higher gut microbial diversity, with a significant increase in beneficial bacteria like Lactobacillus and Bifidobacterium. Furthermore, these bees showed better digestive efficiency and greater longevity.

Future research perspectives

Despite significant progress, many questions remain unanswered, and new research frontiers are opening in the field of fungus-bee interactions. Identifying these future directions is crucial for orienting research efforts towards areas with the greatest potential impact on bee health and beekeeping sustainability.

Synergies between different fungal species

One of the most promising perspectives concerns the study of synergies between different fungal species. If individual fungi have demonstrated specific beneficial effects, it is plausible that strategic combinations of different species could produce synergistic effects superior to the sum of the individual components. Future research should explore these potential synergies, identifying optimal combinations to address specific bee health issues.

Optimization of extraction protocols

The efficacy of fungal extracts critically depends on the extraction methods used. Different active compounds require different extraction conditions (temperature, solvent, time) to be obtained in bioavailable and stable form. Future research should focus on optimizing these protocols, identifying the conditions that maximize the content of active principles and their biological efficacy when administered to bees.

Large-scale studies under field conditions

Most studies conducted so far have involved small groups of bees in laboratory conditions or pilot apiaries. To definitively validate the efficacy of fungus-based approaches, large-scale studies conducted in different environmental conditions and with different bee breeds are needed. These studies should evaluate not only the health parameters of individual bees but also colony-level indicators such as honey production, colony strength, and overwintering success.

Investigation of molecular mechanisms

Although several mechanisms of action have been identified, the understanding of the molecular pathways through which fungal compounds exert their effects on bees is still limited. Deepening this knowledge through omics techniques (transcriptomics, proteomics, metabolomics) could reveal new therapeutic targets and allow the development of more targeted and effective applications.

Bees: towards more sustainable beekeeping through fungi

The in-depth analysis conducted in this article convincingly demonstrates that fungi represent a biological resource of extraordinary value for bee health and, consequently, for global food security. The scientific evidence, although still accumulating, clearly indicates that several fungal species possess immunomodulatory, antiviral, antibacterial, and detoxifying properties that can help bees face the multiple threats of the modern world. Integrating fungi into beekeeping management does not mean replacing existing good practices, but rather enriching the beekeeper's toolbox with innovative, sustainable tools in harmony with natural processes.

Practical implications for beekeepers and mycoculturists

The knowledge presented in this article has concrete implications for various categories of operators. For beekeepers, the strategic integration of fungi into bee health management offers the opportunity to reduce dependence on chemical treatments, improve colony resilience, and contribute to the long-term sustainability of beekeeping. For mycoculturists, a new market of applications opens up that values the medicinal properties of fungi in a context of great ecological and economic relevance. For botanists and mycologists, the fungus-bee relationship represents a fascinating field of interdisciplinary research that deserves to be explored in depth.

Future perspectives

Looking to the future, it is reasonable to expect that the role of fungi in beekeeping will continue to expand as new research provides more solid evidence and practical experiences accumulate. The most exciting prospects include the development of standardized commercial formulations, the identification of new fungal species with beneficial properties, and the integration of fungi into holistic approaches to bee health management that consider the entire ecosystem in which colonies are placed. In a world facing unprecedented environmental challenges, the alliance between bees and fungi represents a powerful reminder that the most effective solutions often derive from understanding and harmonizing existing natural relationships.

Protecting bees through fungi is not just a technical or economic issue but represents a paradigm shift in our relationship with nature: instead of fighting pathogens with substances foreign to the ecosystem, we learn to enhance natural defenses using biological resources that have evolved over millions of years of coexistence. In this sense, fungus-supported beekeeping perfectly embodies the principle that to solve the complex problems created by humans, we must often look to the simple solutions offered by nature.

As research continues to unravel the secrets of this fascinating relationship, it is important that beekeepers, researchers, institutions, and citizens collaborate to translate this knowledge into concrete practices that protect not only bees but the entire food system that depends on them. The future of our food supply might depend, to a greater extent than we imagine, on our ability to value and protect the ancient alliance between bees and fungi.