Surrounding landscape and spatial arrangement of honey bee hives affect pollen foraging and yield in cranberry

Authors: GUZMAN, AIDEE - University Of California; GAINES-DAY, HANNA - University Of Wisconsin; LOIS, ABBY - University Of Wisconsin; Steffan, Shawn; Brunet, Johanne; Zalapa, Juan; GUEDOT, CHRISTELLE - University Of Wisconsin

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2019
Publication Date: 8/28/2019
Citation: Guzman, A., Gaines-Day, H., Lois, A., Steffan, S.A., Brunet, J., Zalapa, J.E., Guedot, C. 2019. Surrounding landscape and spatial arrangement of honey bee hives affect pollen foraging and yield in cranberry. Agriculture, Ecosystems and Environment. 286:106624. https://doi.org/10.1016/j.agee.2019.106624.
DOI: https://doi.org/10.1016/j.agee.2019.106624

Interpretive Summary: Honey bees are the most important managed pollinator in the world, but the demand for their pollination services is growing faster than the available supply. Therefore, it is critical to determine the most efficient management practices to maximize their use for crop production. One factor that influences the efficiency of crop pollination is the availability of alternative flowering resources that bees can visit instead of the crop. These resources can vary as a function of the surrounding landscape of each farm as well as local management practices within a farm. However, little is known about the behavior of honey bees when collecting pollen of the target crop, and how they respond to changes in the physical placement of the hives within a farm or the flower resources of the surrounding area. Overall, on-farm hive placement affected the types of pollen collected by honey bees. Hives near water reservoirs collected a lower proportion of crop pollen. However, number of cranberry pollen grains do not differ by hive location. Also, yield was unaffected by the proportion or number of cranberry pollen grains collected. Rather, yield was dependent on the amount of woodland in the surrounding landscape. The results of this study are important because they suggest that cranberry yield is more strongly influenced by the landscape surrounding the marsh than bee hive arrangement within the marsh. Therefore, this research can help cranberry growers achieve sufficient pollination regardless of where on their marsh hives are placed.

Technical Abstract: Honey bees are the most important managed pollinator in the world. Recent trends suggest, however, that the demand for their pollination services is growing faster than the available supply. Therefore, it is critical to determine the most efficient management practices to maximize their use for crop production. One factor that influences the efficiency of crop pollination is the availability of alternative, non-crop floral resources. These resources can vary as a function of the landscape surrounding a farm as well as local management practices within a farm. However, little is known about honey bees and their foraging behavior on the target crop respond to the spatial arrangement of hives or the composition of the surrounding landscape. In this study, we collected pollen from honey bee hives placed on commercial cranberry marshes in central Wisconsin (USA). Individual marshes were selected to fall within a gradient of surrounding landscape from high woodland to low woodland. Hives were placed within each marsh to be either adjacent to wooded habitat, adjacent to a water reservoir, or in the center of the marsh. We found that hives placed near water reservoirs collected a lower proportion of cranberry pollen than hives at other locations within the marsh. Moreover, the community of plants from which bees collected pollen differed both by hive location and surrounding landscape. Interestingly, there was no difference in the number of cranberry grains collected by hives as a function of their location or the surrounding landscape type. Furthermore, there was no difference in the weight of pollen samples collected by hives as a function of hive location or landscape type. The evenness of pollen collected by hives was lower near water reservoirs than at other locations on the marsh. Cranberry yield did not vary as a function of the proportion or the total number of cranberry grains collected, but yield was higher at marshes located in low-woodland landscapes compared to those in high-woodland landscapes. These results suggest that cranberry yield is more strongly influenced by the landscape context surrounding the marsh than hive arrangement on the marsh. Therefore, cranberry growers should be able to achieve sufficient pollination regardless of where on their marsh hives are placed.