Honey Bees and Bacteria
The decline of one of our favourite pollinators and indicator of the general health of our ecosystems, the honey bee has been in the news a lot in the last decade or so.
Pathogens can be a cause of bee decline although there are many other potential reasons for the decline such as parasites and environmental changes.1
The honey bee's own microbiome can help protect from pathogens. Micro flora in bee colonies can produce antimicrobial compounds that stop the pathogens from growing.2 Research was undertaken where some bee larvae were allowed to grow without gut bacteria. The other bee larvae were given the gut bacteria found in the stomachs of bees within the same nest. Results were that the bees inoculated with gut bacteria developed a greater immunity against pathogens by producing considerably larger amounts of antimicrobial protein.3 This further demonstrates how the bees protect themselves against pathogenic bacteria by using their own beneficial bacteria.
The gut microbiota of a honey bee is very unique. The gut bacteria of a honey bee is mainly made up by 8 types of bacteria that are exclusively found in honey bees with the exception of some bumblebees.4
Honey bee larvae are protected from birth as the queen boosts their immune system by transferring bacteria via a blood protein directly to the developing eggs. This process naturally immunises the young and gives them a better chance at fighting disease. This also helps to explain some ways in which social bees share their bacteria.5
Pathogens found in bee colonies:
Paenibacillus larvae (cause of American Foulbrood)
Melissococcus plutonius (cause of European Foulbrood) 6
American Foulbrood is a very serious bacterial pathogen in bees. It is contagious and can be easily spread by humans and beekeeping equipment. European Foulbrood is a less virulent pathogen. This makes it possible for a colony to recover from the infection.7
Due to the prevalence of Foulbrood, many beekeepers treat their bees with antibiotics. This successfully protects the bees from foulbrood but can affect the bee’s gut bacteria. This is something that needs to be considered as overuse of antibiotics could negatively affect the bee populations in the long run and affect their natural protection (in a similar way to how humans are increasingly affected by antibiotic resistant bacteria).
Some honey bee gut bacteria that produce antimicrobial compounds, particularly strains of lactic acid bacteria could also be used to help humans fight pathogens. In lab tests, the bacteria eliminated pathogens often associated with human wounds. This lab research gives hope for real world uses. At the time that the research was published (2014), this method of healing wounds and counteracting wound pathogens had only been successfully implemented on horses. Further testing could help attain an alternative treatment to antibiotics.8
Further study of the honey bee microbiome can help us gain insight into how we can apply its benefits to our own health. Also, more importantly, it may offer clues to how we can help the bee population and in turn, assist in stalling their decline. Hopefully some significant breakthroughs are close at hand.
1, 2 & 6. Clinita Evette Randolph. Bacteria involved in the health of Honey Bee (Apis Mellifera) Colonies. 2014
- Posted on 2017-04-21 12:01:24