Long-term effects of antibiotic treatments on honeybee colony fitness – a modelling approach

1. Gut microbiome disequilibrium is increasingly implicated in host fitness reductions, including for the economically important and disease-challenged western honey bee, Apis mellifera. In lab experiments the antibiotic tetracycline, which is used to prevent American Foulbrood Disease in countries including the US, elevates honey bee mortality by disturbing the microbiome. It is unclear however, how elevated individual mortality affects colony level fitness.

2. We used an agent-based model (BEEHAVE) and empirical data to assess colony level effects of antibiotic-induced worker bee mortality, by measuring colony size. We investigated the relationship between the duration that the antibiotic-induced mortality probability is imposed for and colony size.

3. We found that when simulating antibiotic-induced mortality of worker bees from just 60 days per year, up to a permanent effect, the colony is reduced such that tetracycline treatment would not meet the European Food Safety Authori...