What's the Buzz with ATTTA #92

Thursday, 31 March 2022

Spring is here and before we know it, wild blueberries will be blooming and ready for pollination. Engaging in wild blueberry pollination is a major undertaking for many Atlantic beekeepers and demand for this service is high. In the upcoming blogs, we will discuss some important aspects to consider for successful pollination.

Honey bee stocking density on wild blueberries

How many honey bee hives should be placed on a wild blueberry field for pollination? It is an important question that blueberry producers consider when ordering honey bee hives for the upcoming season. Unfortunately, the answer is not absolute. It depends on the situation of the field and will vary each season. The complexity of this interaction can be realized when looking at the model shown in Figure 1. The number of honey bee colonies placed for pollination would be reflected in the bee foraging density indicated in the model.

Fig. 1. Conceptual model of wild blueberry bloom (solid arrows are positive causal relationships, dashed arrows are negative causal relationships, and dotted arrows are positive or negative relationships depending upon the independent factor; numbers at base of arrows are literature citations documenting relationships). 
(Asare et al., 2017)

Honey bees are not the only pollinators of wild blueberries. The presence of wild pollinators impacts the demand on honey bees, in that fewer wild pollinators call for more managed pollinators. The population of wild pollinators can be measured in a field to get an estimate of the pollination force they will provide (Drummond 2002). However, this can only be performed once blooms are out, well after honey bee orders should be organized. Nonetheless, gaining a deeper understanding of the wild pollinators across fields each season can help producers decide where to allocate honey bee hives. Wild pollinator populations are subject to fluctuation between years, so be careful in using one year’s population to predict future demands. Honey bees are useful in reducing the risk associated with relying solely on fluctuating populations of wild pollinators.

Other important considerations are the species of wild blueberries being cultivated as well as other flowering plant species that exist within and around the edge of the field. More than one species of wild blueberry plants may grow together on a field, for example Vaccinium angustifolium and Vaccinium myrtilloides. This is important to recognize as unfortunately, these two species are not compatible in pollination. Simply put, blueberry pollination is successful when an insect collects pollen from one flower and carries it to another flower of a compatible species (Eaton et al. 2004). V. angustifolium and V. myrtilloides are not compatible, so the transfer of pollen between flowers will not result in a harvestable berry. This is sometimes the reason why one field stocked with honey bees can see such a greater improvement in pollination than another. On a field mixed with these two blueberry species, pollination may not improve with higher numbers of pollinators because pollination has not been successful. On the other hand, if there is compatibility between plants, for example on a field with only V. angustifolium, increasing pollinator numbers can significantly increase pollination success.

Other flowering plant species within and around a wild blueberry field will impact the demand for managed honey bee colonies, as well. Surrounding flowering species might attract pollinators and draw some of the pollination force away from the wild blueberries. Nonetheless, these neighboring floral species can provide important habitat for wild pollinators.

In consideration of all of these variables, there are general recommendations for honey bee hive stocking densities on wild blueberry fields. For example, the University of Maine Cooperative extension recommends small fields with little floral surrounding should be stocked at two hives per acre. Comparatively, small fields with many competing floral species should be stocked at two to three hives per acre. On a large field, the recommendation is to increase to three to five hives per acre. The table below lists a range of recommendations and their sources. Next week, we will compare and elaborate on these recommendations.

Stocking Density (Hives/Hectare)

Hive number



10 (range 4.5–12.5)


Asare et al., 2017



McCallum et al., 2020

5 – 7.5



5 – 12


Eaton, Murray, et al. 2004

Asare, E., Hoshide, A.K., Drummond, F.A., Criner, G.K. and Chen, X., 2017. Economic risk of bee pollination in Maine wild blueberry, Vaccinium angustifolium. Journal of Economic Entomology110(5), pp.1980-1992.
Drummond, Frank. 2002. “629-Honey Bees and Blueberry Pollination.” The University of Maine Cooperative Extension. https://extension.umaine.edu/blueberries/factsheets/bees/629-honey-bees-and-blueberry-pollination/.
Eaton, L.J., Kenna MacKenzie, Dale McIsaac, and John Murray. 2004. “Lowbush Blueberry Fact Sheet: Pollinating Wild Lowbush Blueberries in Nova Scotia.” https://www.perennia.ca/wp-content/uploads/2018/04/pollinating-wild-lowbush-bluberries-ns.pdf.
Eaton, L.J., John Murray, Dale McIsaac, and Kenna MacKenzie. 2004. “Lowbush Blueberry Fact Sheet: Use of Honey Bee Colonies for Pollinating Wild Lowbush Blueberries.” https://www.perennia.ca/wp-content/uploads/2018/04/use-of-honeybee_colonies-pollinating-wild-lowbush-blueberries.pdf.
NB DAFF (ND) Managing Honey Bee Hives for the Pollination of Wild Blueberries. Wild Blueberry Factsheet B.3.0
Robyn McCallum, Cameron Menzies, Kathleen Glasgow, and Sawyer Olmstead, 2017 Evaluating the Effect of Honey Bee Stocking Density on Bee Growth and Fruit Development in Wild Blueberry. Atlantic Tech Transfer Team for Apiculture: Fact Sheet.

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