Bees, berries, and borage: Recruiting wild pollinators in a strawberry agroecosystem
Bees need flowers and flowers need bees. This is one of the simplest lessons of the natural world, but as a graduate student in the Department of Horticultural Science, Nathan Hecht wants to know more about what this means specifically for Minnesota food production. How can our understanding of ecology inform the way we design our agricultural systems? That is, how can we create agricultural landscapes that are both more productive and sustainable?
Hecht’s research examines the question of whether wild pollinators can be recruited to pollinate a strawberry crop by planting insect-attractive flowers nearby. This is an “if you plant it, they will come,” sort of strategy. While providing resources and habitat for wild pollinating insects isn’t a new strategy, the practice has been gaining popularity as evidence of its benefits for food crops has risen in the scientific community. Given the decline in observed honey bee colonies, “pollinator farmscaping” has received increased consideration as a way to ensure the continued presence of pollinators for pollination-dependent crops.
Hecht’s field research takes place at the West Central Research and Outreach Center (WCROC) in Morris, Minnesota, where he works with lead horticultural scientist Steve Poppe to manage a two-year pollinator farmscaping experiment.
In the 2017 growing season, the team planted a patch of borage (borago officinalis), a blue, star-shaped, edible herb on one end of three plots of day-neutral strawberries, a variety of annual strawberry plants that can be grown from June to October. One of Hecht’s roles is to collect data on strawberry fruit production and insect presence and examine how these variables change with distance from the flower patch. The hypothesis? Strawberry flowers closer to the borage flower patch will receive more insect visits, be more fully pollinated, and produce bigger, higher quality strawberries.
Each borage patch hosts a wide variety of insects, including bumble bees, honey bees, native bees, flies, and other nectar-loving insects. Most of the insects found on strawberry flowers in Hecht’s experiment are either small native sweat bees or hover flies, a family of flies that often mimic bee behavior.
While the team only has data from the first year of the experiment, the results are promising and may lead to more wide-scale economic and ecological benefits to pollinator farmscaping. When planted within 50 feet of a borage flower patch, individual berry weights tended to be higher than berries harvested at the far end of the row, and heavier berries may mean heavier profits for growers.
Time will tell if the pattern continues, but providing a nearby habitat for bees and other pollinators could help strawberry growers increase their bottom line and, at the same time, help support and conserve wild pollinator populations.
There are many ways to incorporate pollinator farmscaping practices into your own home garden or a large-scale farm. This can begin with simply mowing less often, to allow early season flowers like clover and dandelions to thrive when other floral resources are low. Planting annual flowering species can be one way to experiment with flower plantings at low cost and with little risk. Some flower strips could even serve as secondary crops, as many species are edible, have medicinal properties, or can be sold as cut-flowers. More long-term efforts could include perennial flower plantings or even restored prairie landscapes. The Xerces Society (xerces.org) has many resources available to help design and integrate these sorts of practices on farms.
By Nathan Hecht
Nathan Hecht is a Master’s student in the Organic and Sustainable Horticulture Lab at the University of Minnesota. He was the first place winner of the Organic Research Forum Poster Competition during the MOSES 2018 Conference.