Juanse pointed us to this paper:-

http://www.pnas.org/content/early/2012/06/13/1202970109.full.pdf

I thought it to be very informative, so I will go ahead and "light the blue 
touch paper". (I can already hear Randy groaning!).

Thanks Juanse.

What a fantastic paper! It certainly broadened my understanding of what 
seems to be happening in the bees gut.

I know the experts will say you can't draw any conclusions based on such a 
small sample size, but I will anyway.

From a practical perspective, if I understand correctly, bees exposed to 
fungicides (and antibiotics) could therefore have their following functional 
abilities compromised via disruptions to their gut microbiota:-

1)    Biofilm formation in the midgut inhibited, thereby reducing their 
protection against gut pathogens such as nosema
2)    Disruptions to the symbiotic metabolism of plant-derived carbohydrates 
which would otherwise be toxic to the bee (eg mannose and melibiose)
3)    Disruptions to the symbiotic microbiota conferred efflux mechanisms 
which provide specific antimicrobial benefits to the bee, and indeed as a 
result are found in                some honeys
4)    Disruptions to the symbiotic digestion of the disaccharide sucrose 
into fructose and glucose, one of the most common sugars in nectar
5)     Disruptions to the rupture and digestion of the pectin-rich exine 
coating of the pollen grains by the symbiotic microflora, thereby 
compromising the bees ability to             access the contents for 
essential nutritive conversion. (I previously assumed this happened largely 
in the comb fermentation process of pollen to bee bread. But 
unsurprisingly, it obviously happens internally in the beegut too.).
6)     Because pectin has been shown to be toxic to bees, its catabolic 
breakdown by bacteria in the mid-gut could simply permit bees to avoid 
intoxication, and inhibition         of that too could be quite detrimental 
to bee fitness.

Have I missed anything?

PeterD
In Western Australia, about to start our first migration to newly 
established almond orchards. 

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