Biofilms in bee colonies

Regarding to my presentations on microbial processes occurring in hives I addressed, among other subjects, to the formation of biofilms and the bees. A biofilm is a bacterial mass, which is covered by an impermeable layer on top. By bacterial overgrowth, which occurs in humid conditions, respiratory channels (trachaea) of bees can be closed by such a biofilm. Then the bees won’t get enough oxygen. Subsequently an anoxic situation is being created in the body of the bee. Within 5 minutes the result is a reduction in the energy production by 90%, with all its consequences for the activity of the bees and their health.

Another example of a biofilm in the case of bees is to be found in the bee’s bread. As follows:
Bee bread = nectar + pollen
First, growth of ordinary bacteria (+ oxygen)
These bacteria close the oxygen supply (biofilm) and make the conditions anoxic.

After that the lactic acid bacteria will grow (- oxygen)
Minerals from pollen are released ( e.g. Fe2+, Mn2+, Zn2+)
The process in the hive resembles on what is happening in wine production. First the yeasts will grow, which produce a lot of CO2. Due to this excess in CO2 production, oxygen is then repelled and an anoxic situation is created. Then other microorganisms will grow.
In the picture beneath is showing an electron micrograph of pollen grains with thereon lactic acid bacteria (3.500x magnification).

foto van Maarten van Hoorn.