Fungal Strain Adaptation Found to Benefit the Health of Honey Bee Colonies

Honeybees are a keystone species for the environment since they are largely responsible for pollinating much of the world’s crops and wild plants. Without bees, entire ecosystems would shatter, and global food security would be at risk. Unfortunately, honey bee populations have substantially declined over the past few decades due to factors like habitat loss, diseases, climate change, and pesticide use. However, recent research has uncovered a beneficial relationship between the fungus Aspergillus flavus and the Western honey bee, highlighting potential strategies to support bee populations.

Bee bread and its role in the hive

Bee bread, a staple for honeybees, is made from a combination of bee pollen, saliva, and nectar. The mixture is stored in honeycomb cells and fermented, creating a nutrient-rich substance that is crucial for the survival of larvae and young bees. The fermentation of bee bread is necessary to preserve its nutrient content and prevent it from spoiling. This food source is a major determinant of colony health, since it ensures the hive has a continuous supply of essential nutrients.

Adaptations of A. flavus

The Aspergillus flavus fungus is frequently found in bee bread, yet researchers wanted to determine what adaptations it has gone through to survive in such conditions. They found that an isolated strain of A. flavus has a higher tolerance to acidic conditions, low moisture levels, and exposure to propolis—a material made by bees that has antimicrobial properties. Compared to the A. flavus strains not found in beehives, the isolated strain appeared to have remarkable adaptations that allowed it to survive in conditions typical of a hive environment.

Although beehives have mechanisms to protect themselves from microorganisms, A. flavus’s adaptations allow it to thrive there. According to genetic analysis, specific gene variants enhance the fungus’s ability to survive in such harsh conditions. These genetic traits demonstrate the link between A. flavus and honey bee hives, as they appear to work together well.

A symbiotic relationship

The adaptations of A. flavus not only allow it to survive in the hive but also suggest a mutually beneficial relationship between the fungus and honey bees. The presence of A. flavus in bee hives helps preserve and ferment the bee bread, ensuring it remains free from spoilage. Additionally, A. flavus was found to contribute to a more balanced microbial environment in the hive, protecting it from pathogenic microbes.

In return, A.flavus has a safe place to stay and a source of nutrients to feed on. The antimicrobial conditions of the hive also limit competition from other microorganisms, allowing the fungus to thrive and continue benefitting the overall health and well-being of the bee colony (1).

Implications for bee populations

This new understanding of A. flavus’s role in bee colonies can guide us toward better management strategies to support the health of bees and the stability of their hives. Microbial interactions are significant to hive health, and these findings offer new ways to conserve threatened bee populations. By supporting the natural balance of beneficial fungi like A. flavus, scientists can enhance the resilience of bee colonies against environmental stressors, ultimately protecting these vital pollinators and their populations.

References

1. Bush, Daniel S, Bernarda Calla, and May R Berenbaum. 2024. “An Aspergillus Flavus Strain from Bee Bread of the Western Honey Bee (Apis Mellifera) Displays Adaptations to Distinctive Features of the Hive Environment.” Ecology and Evolution 14 (2). https://doi.org/10.1002/ece3.10918.