pesticide, microbiota and seasonal diet

The Beekeeping Today Podcast discussion of "Winter Bees, Summer Bees and Imidacloprid" led me to dig into that journal article topic. The assumptions in the article are:

• Naïve lab bees fed clean syrup that had no transfer of bacteria and microbiota by contact with other adult bees are more sensitive to stressors and therefore avoid the highly toxic neonicotide Imidacloprid (IMP) in the caged challenge
  
• Winter bees live longer (estimated age of 2 to 3 months) and accumulate more intestinal microbiota and are therefore less sensitive to IMP
  

Influence of honey bee seasonal phenotype and emerging conditions on diet behavior and susceptibility to imidacloprid concludes:

• Winter bees preferred IMP-tainted syrup at both 5 and 20 PPB
  
• Summer bees' preference for IMP-tainted syrup was neutral
• Naïve summer bees that emerged in a lab (not exposed to other adult bees and fed clean syrup) avoided IMP-tainted syrup in the caged challenge
  

 method and materials:

• 2700 winter and summer bees in 27cages (100 bees/cage) were challenged with IMP tainted syrup (5 and 20 PPB)
  
• 3 syrup feeding setups
• 1:1 versus 1:1 untainted (clean) syrup; control 1 versus control 2
  
• swapped locations; 1:1 versus 5 PPB (sub-lethal, next to nothing concentration)
  
• swapped locations; 1:1 versus 20 PPB (lethal concentration)