Effect of pollen on survival under field conditions. 

Excerpts for review purposes only:

To determine if the positive effect of dietary pollen on bee survival, observed under laboratory conditions, could also be observed under more complex  eld conditions, we removed the stored pollen and balanced the bee populations and mite infestation levels in 8 colonies in late Summer. Subsequently, we provided 4 of the colonies with 50 g of pollen per week, for one month, and left  the other 4 colonies as untreated controls.

At the end of September, despite a chemical treatment to control Varroa levels following the trial, two out of four colonies that received no pollen died but all the pollen-treated colonies survived. By the end of November, all of the colonies that received no pollen were dead, while two of the pollen-treated colonies survived. Overall, though there is a great amount of biological variability in these  field studies and the sample size is small, these preliminary results suggest a positive effect of dietary pollen on bee survival under  field as well as under lab conditions.

Our results indicate that access to dietary pollen can mitigate the negative impact of Varroa mite infestation and the related viral infection in caged honey bees, under laboratory conditions. Our field experiment suggests that pollen supplementation improved the survival of honey bee colonies in the  eld, with all 4 of the control colonies dying and only 2 of the four pollen-supplemented colonies dying. While these outcomes support the results from our laboratory studies, clearly the sample size is limited ...

In conclusion, based on the results described here, we can state that pollen represents an essential component of bees’ nutrition whose properties go well beyond the supply of essential amino acids or metabolic energy. In particular, it appears that the apolar components of this food can provide important tools for the maintenance of the honey bee’s homeostasis including energetic and water balance and allow the coexistence with the rich cohort of symbionts inhabiting the hive.

"Elucidating the mechanisms underlying the beneficial health effects of dietary pollen on honey bees (Apis mellifera) infested by Varroamite ectoparasites." Annoscia, Desiderato, Virginia Zanni, David Galbraith, Anna Quirici, Christina Grozinger, Renzo Bortolomeazzi, and Francesco Nazzi. www.nature.com/scientificreports

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