Hi all

A few years ago, when there was widespread interest in injecting ash trees with pesticides against the emerald ash borer, I raised the question as to whether these substances, especially ememectin, might be collected by bees via ash pollen. There was a lot of pushback, people were stating that ash is a wind pollinated tree, bees don't collect ash pollen, etc. 

I trapped pollen during the ash bloom period but could not get anyone to analyze it for me. Now, a new paper by Reed Johnson, et al, confirms that honey bees do in fact collect ash (Fraxinus) pollen. They show percentages on April 29, bee pollen collected contained 

25% Taraxacum officinale (dandelion)
22% Acer (maple)
51% Fraxinus (ash)

Pollens of trees in the genera Acer L. and Fraxinus L., both
anemophilous, were the most abundant pollens on the three
earliest sampling dates. On May 6, more than 90% of the total
sample originated from entomophilous woody species, corresponding
with the full bloom of rosaceous trees (e.g., Malus, Prunus L., Crataegus L., and Amelanchier)

Richardson, R. T., Lin, C. H., Sponsler, D. B., Quijia, J. O., Goodell, K., & Johnson, R. M. (2015). Application of ITS2 metabarcoding to determine the provenance of pollen collected by honey bees in an agroecosystem. Applications in Plant Sciences, 3(1).

PLB

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