ProApis Project Initial Outcomes: Probiotics to mitigate the effect of pesticides on Apis mellifera bees

Currently, the use of pesticide has increased worldwide. These chemicals are one of the main factors of the colony collapse disorder (CCD), contributing significantly to the loss of honey bees due to their low detoxifying capacity. The honey bee gut microbiota is diverse and carries out several important functions which contribute to their nutrition, digestion, defence against pathogens, and insecticide resistance, therefore improving their immune system and health.
ProApis is a project with a biotechnological approach in search of viable solutions to mitigate the negative impact of pesticides on the health of bees. The main objective is to investigate the gut microbiota of Apis mellifera bees exposed to sublethal doses of glyphosate (herbicide) and boscalid (fungicide) under in vitro conditions, in search of tolerant and degrading bacteria.
In order to do this, honey bees were sourced from three distinct apiaries in Ireland during the summer season. Subsequently, these bees were kept in vitro in laboratory cages. Oral exposure tests to pesticides were carried out by feeding the bees with sucrose syrup at 50% (w/w) supplemented with three concentrations (0.5 -1 -3 mg/L) of the commercial glyphosate and boscalid formulations. Following a 15-day exposure period, gut bacteria were isolated from the bees from the treatments and molecular identification was carried out by 16s rRNA sequencing.
Survival of bees orally exposed to pesticide was above 55% for boscalid and 60% for glyphosate. There were not significant differences in daily syrup consumption of different pesticide treatments compared to the control. More than 100 bacteria were isolated from each chemical challenge. Analysis of the 16S rRNA gene sequence indicated that some bacteria belong to Lactobacillus helsingborgensis, L. apis, L. melliventris, Bifidobacterium asteroids, B. polysaccharolyticum, B. mizhiense, Gilliamella apicola, among others.
In summary, the initial results of the ProApis project, performed in Irish honeybees, indicates the presence of bacteria which exhibit promising mitigating effects of sublethal pesticide exposure. These bacteria could have a potential application for probiotics to improve bee survival in a polluted environment