Specialty oilseed crops provide an attractive source of pollen for beneficial insects

Authors: THOM, MATTHEW - University Of Minnesota; EBERLE, CARRIE - University Of Wyoming; Forcella, Frank; Gesch, Russell - Russ; Weyers, Sharon

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2017
Publication Date: 5/2/2017
Publication URL: https://handle.nal.usda.gov/10113/5852106
Citation: Thom, M., Eberle, C., Forcella, F., Gesch, R.W., Weyers, S.L. 2017. Specialty oilseed crops provide an attractive source of pollen for beneficial insects. Journal of Applied Entomology. 1-12.

Interpretive Summary: Honey bees and native pollinators need pollen as sources of protein, fats, and micronutrients. Without natural pollen, pollinators, like honey bees, are more susceptible to several diseases and other maladies. In regions dominated by intensive agriculture, too few wildflowers exist to supply the pollen needed for sustained health of pollinators. However, agriculture also can help diminish this problem by increasing crop diversity, particularly of specialty oilseed crops that are highly attractive to pollinators. We examined pollen production and pollen protein concentration of a dozen specialty oilseed crops that are adapted to the Upper Midwest of the United States. Some of these crops, like flax, produced very little pollen. In contrast, oilseed echium, whose highly valued seed oil is used in the cosmetic industry, produced enough pollen in one acre to support the entire annual requirements of 10 honey bee colonies, i.e., about 400 lbs of pollen per acre, about half of which was protein. The remaining crops had intermediate levels of pollen production (50 to 150 lbs/acre). These crops included borage, calendula, canola, crambe, and cuphea. Pollen production levels were correlated coarsely but positively with intensities of pollinator visitation across crop species. This information should be useful for bee keepers and resource conservationists charged with solving the continuing pollinator crisis in the nation.

Technical Abstract: The continuing pollinator crisis is due, in part, to the lack of year-round floral resources. In intensive farming regions, such as the Upper Midwest (UMW) of the USA, natural and pastoral vegetation largely has been replaced by annual crops such as corn, soybean, and wheat. Neither the energy (nectar) nor protein (pollen) needs of pollinating insects are being met sufficiently by these landscapes. Several potentially useful oilseed crops can be grown in the UMW, and many of these oilseeds are highly attractive to pollinators. Prior research showed that some of these oilseeds produced abundant nectar, but their corresponding values for pollen production are unknown. Accordingly, the aim of our research was to document pollen (and protein) production per unit area of a dozen oilseed crops grown in Minnesota and associate these values with levels of insect visitation during anthesis. Our results show that oilseed crops such as camelina, flax, and pennycress produce relatively little pollen (= 40 kg/ha) and pollen protein; borage, calendula, canola, crambe, and cuphea produce bountiful pollen resources (50 to 150 kg/ha); and oilseed echium generates massive amounts of pollen (>400 kg/ha), about 50% of which is protein. Insect visitation to flowers of these plants was correlated positively with pollen and pollen-protein production. In summary, if UMW landscapes are to be diversified in the future, some alternative oilseed crops, like oilseed echium, are far superior in producing pollen than other crops like flax.