Honey bees and their gut microbes have coevolved over millions of years into a complex symbiotic relationship vital for bee health, according to new research published this week. This breakthrough study provides unprecedented insight into how bees produce nutrients to feed their microbiome, unveiling a metabolic interdependency underpinning the global pollination services bees provide.
Bees Manufacture Carboxylic Acids to Nourish Gut Bacteria
Scientists have discovered that honey bees synthesize carboxylic acids which are then metabolized by their gut microbiota, comprising a mix of dozens of bacterial species dominated by the Snodgrassella alvi species. This revelation comes from a new study published in Nature Communications by researchers from Vanderbilt University.
Using advanced genetic analysis and imaging techniques, the researchers found bees produce acetate, lactate and succinate – simple carboxylic acids – in their fat cells. These nutrients are then absorbed by S. alvi bacteria populating the bee gut. In return, S. alvi provides the bee with essential amino acids and vitamins it cannot produce alone.
“Our study unveils an elegant symbiotic relationship between bees and their gut microbes underpinned by metabolic exchanges essential for health,” said lead author Dr. Philipp Engel, Assistant Professor of Biological Sciences. “This lays the foundation for future research into how disruptions to this delicate balance could impact bee populations already under threat from disease, parasites and habitat loss.”
Widespread Effects From Gut Microbiome Decline
Rising concerns over global bee population declines in recent decades has placed increasing focus on factors impacting bee health. Dysfunction of the crucial gut microbiome could have far-reaching consequences not just for bees but human agriculture and food security.
Bees play a vital ecological role through plant pollination services enabling productive harvests for over 90 commercial crops globally including fruit, vegetables and nuts. As solitary foraging insects prone to stress and illness, bees require a healthy gut microbiome to strengthen immunity, digestion and nutrient absorption. Disruptions can increase susceptibility to pathogens, reduce longevity and affect brood care for future generations.
“A delicate yet mutually beneficial relationship exists between bees and bacteria,” said co-author Dr. Elina Niño, Professor of Entomology at University of California. “Damage to either side of this balance through things like pesticide exposure and poor nutrition could tip the whole system into decline with potentially devastating flow-on effects.”
Understanding drivers behind disturbances in bee-microbe symbiosis will be key for protecting bee populations.
Factors Impacting Bee Gut Microbiota
Various external and internal variables can positively or negatively influence gut microbiota in bees. These include:
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Pesticide exposure – chemical residues impair gut permeability and inhibit growth of beneficial bacteria. Sub-lethal doses over time weaken immunity.
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Poor nutrition – lack of diverse pollen sources limits nutrients bees manufacture to feed gut microbes. Stunts microbiota.
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Pathogens – viral, fungal and bacterial diseases like nosema directly attack gut lining and alter microbiome makeup.
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Genetics – bee generational lines show differing gut microbiota even in same hive location showing heritability factor.
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Environment – urban settings, climate, landscape and plant biodiversity impact variability of microbiome between bee species and locations.
| Factor | Effect on Gut Microbiota |
|---|---|
| Pesticide Exposure | Impaired gut permeability, inhibited growth beneficial bacteria, weakened immunity |
| Poor Nutrition | Limits ability to manufacture nutrients to feed microbiota, stunts microbiota |
| Pathogens | Attack gut lining, alter microbiome makeup |
| Genetics | Generational bee lines show differing gut microbiota indicating heritability |
| Environment | Urban settings, climate etc causes variability in microbiome between locations and species |
Experts emphasize creating healthy bee habitats with pesticide controls and diverse vegetation as key to supporting gut health. Probiotic supplements show promise helping bees fight pathogens and digestive disorders. Future microbiome research aims to unlock the nuanced interplay between different gut phylotypes to identify core microbial assemblages most vital for bee immunity and development.
Global Action to Protect Bees Now Critical
The findings come the same week as over 50 countries approved a proposal to boost global coordinated efforts to monitor and safeguard global pollinator populations from further declines.
The Multilateral Scientific Panel for Sustainable Pollination will coordinate research and policy initiatives between nations and institutions to identify key risks to pollinators and develop mitigation strategies. The panel plans to integrate gut microbiome science into policy recommendations to governments.
Panel President Sir Robert Watson said the mass dependence of agriculture on bee populations meant their survival was imperative for future food security as the global population heads towards 10 billion by 2050. ThePanel’s proposal argues global pollinator decline has reached a tipping point requiring urgent collaborative intervention.
“Bees are the glue holding ecosystems together through global pollination services and we must act swiftly to prevent irreversible damage,” Sir Watson stated. “Every country has a shared responsibility to understand risks to pollinators and build joint scientific capabilities and policy guard-rails to ensure sustainable pollinator populations.”
Ongoing Bee Microbiome Studies
In related studies presented at the American Society for Microbiology conference this month, new insights are shedding light on how various factors shape the bee gut microbiome:
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Canadian researchers show specific gut microbiota strains provide vital support for bee’s immune system and pathogen resistance. These core microbes could form basis of probiotic treatments to boost colony immunity.
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Brazilian scientists reveal key amino acids produced by S. alvi increase short-term memory and spatial navigation in bees. Declining gut bacteria affects cognitive abilities and foraging behaviors.
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US Department of Agriculture bee lab experiments demonstrate pesticide residues severely deplete beneficial Lactobacillus bacteria over successive generations, allowing harmful pathogens to proliferate.
Findings collectively indicate maintaining a healthy, stable digestive microbiome is pivotal for bee cognitive function, immunity and overall resilience. Researchers emphasize creating supportive environments low in toxins and high in nutrition is key to bolstering gut symbionts and thus sustaining global pollinator populations.
With bee microbiota intricately tied to individual and colony welfare, ongoing disturbances pose risks for mass population decline which would have devastating ecological and economic consequences worldwide. Experts argue discoveries showing the integral interdependency between bees and their microbes provides a critical mandate for global efforts to monitor and safeguard pollinator health. Sustaining future food production and ecosystem stability largely hinges on prioritizing protection of the hidden digestive universe within bees enabling their very survival.
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