What' the Buzz with ATTTA #94

Thursday, 14 April 2022

This week, we will continue our discussion of wild blueberry pollination using honey bees. After stocking density, another consideration for wild blueberry producers is hive placement. It is important to have hives placed in an accessible location for beekeepers, and beyond that there are questions of spacing for maximum pollination. Today we will discuss hive placement on wild blueberry fields for optimal pollination services.

Hive placement for wild blueberry pollination

ATTTA began research in the 2021 field season to measure the distance that honey bees will successfully pollinate blueberry blooms in proximity to their hive. Our assessment included five points, the first of which was in the blueberry field near the recently placed hives.  From this point we continued across the field in a “W” shaped pattern to cover approximately +150m across the breadth of the field. At each of five field locations, we assessed 200 blueberry stems to establish the percent fruit set, percent of harvestable berries, and the berry weight over the course of three visits. 

In the ten fields we visited in both Nova Scotia and New Brunswick, we found no statistically significant difference in percent fruit set, harvestable berries, nor berry weight based on the distance of the sample location from the hives. This suggests that at a minimum of 150m from their hives, honey bees will evenly pollinate all blooms. Given these results, wild blueberry flowers should be consistently pollinated across a field if hives are placed in 300m increments.

Figure 1. Sampling sites (A – E) in the trial fields (n = 10) for three plant assessments. A) Fruit set as percent of bloom at all five field sampling sites. B) Fruit at harvest as a percent of blossom for all five field sampling sites. C) Final berry weight in grams just prior to harvest at all five There was no significant difference (p > 0.05) seen between any of the site locations across the three plant assessments.

Published research papers have also demonstrated that distance is not a limiting factor in successful honey bee pollination on wild blueberry fields, within the range of study. A simulation comparing the pollination services of honey bees, bumble bees, and solitary bees on fields in Maine demonstrated that unlike bumble bees and solitary bees, the distance of a honey bee hive from blueberry blooms did not significantly effect fruit set (Qu and Drummond 2018). In the simulation, bumble bee and solitary bee populations both showed reduced pollination activity, measured by fruit set, as the insects had to travel further from their hives and nests to pollinate clones. Honey bee foraging behavior is thought to play a role in this observation. When a foraging honey bee finds a source of nectar or pollen, she will return to the hive to tell other foragers about this source. In what is called the waggle dance, individual bees are able to provide other foragers with directions to this desirable location. As such, far away forage can be revisited multiple times and a honey bee colony can efficiently explore a large area (Tereshko and Loengarov 2005)

Given that our results did not reach a limit of successful pollination, it is possible that honey bees will pollinate wild blueberry blooms beyond 150m from the hive. They can certainly be found at greater distances from their hives. An early study of honey bee pollination on wild blueberry fields in Quebec found that honey bee densities in a field did not begin to significantly drop until the hives were beyond 3km from the location in question (Aras, De Oliveira, and Savoie 1996). Before this point, honey bee density was measured to be well over 10 per 2m2

The results of our research and relevant publications suggests that honey bees are steady pollinators in wild blueberry fields. Our results reflect that hive placement every 300 meters should provide consistent pollination throughout a field. Stay tuned for more as we carry on with our pollination series in a discussion of hive strength for pollination in a subsequent blog.

Aras, Philippe, Domingos De Oliveira, and Lorraine Savoie. 1996. “Effect of a Honey Bee (Hymenoptera: Apidae) Gradient on the Pollination and Yield of Lowbush Blueberry.” Journal of Economic Entomology 89 (5): 1080–83. https://doi.org/10.1093/jee/89.5.1080.

Qu, Hongchun, and Frank Drummond. 2018. “Simulation-Based Modeling of Wild Blueberry Pollination.” Computers and Electronics in Agriculture 144 (January): 94–101. https://doi.org/10.1016/j.compag.2017.11.003.

Tereshko, Valery, and Andreas Loengarov. 2005. “Collective Decision-Making in Honey Bee Foraging Dynamics,” 8.

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