Specialty oilseed crops provide an abundant source of pollen for pollinators and beneficial insects

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 In intensive farming regions, such as the Upper Midwest (UMW) of the USA, natural and pastoral vegetation largely has been replaced by annual crops such as maize (Zea mays L.), soyabean (Glycine max L.) and wheat (Triticum spp.). Neither the energy (nectar) nor protein (pollen) needs of pollinating and other beneficial insects are being met sufficiently by the new, high-intensity, agricultural landscape. Several potentially useful oilseed crops can be grown in the UMW, and many of these oilseeds are highly attractive to beneficial insects. 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 twelve oilseed crops grown in Minnesota and associate these values with levels of beneficial insect visitation during anthesis. Our results show that oilseed crops such as camelina (Camelina sativa L.), flax (Linum usitatissimum L.) and pennycress (Thlaspi arvense L.) produce relatively little pollen (≤40 kg/ha); borage (Borago officinalis L.), calendula (Calendula officinalis L.), canola (Brassica napus L.), crambe (Crambe abyssianica Hochst) and cuphea (Cuphea viscosissima Jacq. × Cuphea lanceolata W. T. Aiton) produce bountiful pollen resources (50-150 kg/ha); and oilseed echium (Echium plantagineum L.) generates massive amounts of pollen (>400 kg/ha), about 50% of which is protein. Our study is unique in presenting a season-long perspective of pollen production in alternative oilseed crops, a resource valuable to pollen-feeding insects such as managed and wild bees.Diversification of UMW landscapes that includes alternative oilseed crops such as oilseed echium and cuphea can potentially provide a ready source of pollen and protein to help combat pollinator decline. K E Y W O R D SAgroecology, Apis mellifera L., cover crops, hymenoptera, natural enemies, nutrition | INTRODUCTIONThe world is experiencing an unprecedented decline in pollinating insects, including managed species like the honey bee, Apis mellifera L., as well as wild bee species (Potts et al., 2010). Many factors are at play, including habitat loss, disease, parasites, stress and pesticide exposure (Anderson & East, 2008;Brown & Paxton, 2009;Ricketts et al., 2008;Szabo, Colla, Wagner, Gall, & Kerr, 2012;Watanabe, 2008). Loss of habitat due to agricultural intensification and a reduction in plant biodiversity is one of the main contributors to the decline observed in pollinators (Ellis, Evans, & Pettis, 2010;Potts et al., 2010). Diversifying agriculture to include mass-flowering crops which provide essential Published 2017. This article is a U.S. Government work and is in the public domain in the USA. ). The value of these crops as forage resources to pollinators is limited. Maize and wheat are both wind-pollinated grasses, and do not produce nectar. Although maize pollen...

Reduced Potential for Nitrogen Loss in Cover Crop–Soybean Relay Systems in a Cold Climate

“…On the other hand, the total production of both crops, particularly for oil content, can exceed that of monoculture soybeans, which might provide an economic incentive for adoption (Gesch et al, 2014;Berti et al, 2015;Ott et al, 2018). This combination of economic viability, environmental benefits such as floral resources for pollinators (Eberle et al, 2015;Thom et al, 2018), and the potential to reduce nutrient loss, which was established by N and P uptake and soil and soil-water dynamics in the current study, indicates that autumn-seeded, overwintering oilseed crops can provide an opportunity to increase cropping system diversity and improve economic and environmental outcomes.…”

Honey Bee (Hymenoptera: Apidea) Pollen Forage in a Highly Cultivated Agroecosystem: Limited Diet Diversity and Its Relationship to Virus Resistance

“…Pollen is a critical source of nutrition as it supplies proteins, lipids, and micronutrients ( Wright et al 2018 ). In agricultural landscapes with cropland as the dominant land cover, some mass-flowering crops, like sunflower and oilseed rape, can provide honey bees large quantities of pollen in a short period ( Requier et al 2015 , Thom et al 2018 ). However, a preponderance of only a single species could contribute to reduced nutritional value of pollen for honey bees ( Schmidt 1984 ; Schmidt et al 1987 , 1995 ; Di Pasquale et al 2013 ; Nicolson and Human 2013 ).…”

Weather and landscape influences on pollinator visitation of flowering winter oilseeds (field pennycress and winter camelina)

“…Flowering of no other crops in this region is so early; even winter canola ( Brassica napus L.), which lacks sufficient hardiness to be grown commercially in the region, begins flowering much later than pennycress and camelina (Eberle et al., 2015). Consequently, native and domesticated insects that emerge from over‐winter nests or commercial beehives in April through June near fields of pennycress or camelina have access to copious supplies of nectar (sugar equivalent of 50–100 kg/ha) and pollen (protein equivalent of about 10 kg/ha) from these mass‐flowering crops (Eberle et al., 2015; Thom et al., 2018).…”

“…(2015) and Thom et al. (2018) were performed in eastern South Dakota and adjacent western Minnesota. No other information is available about pollinators on camelina and pennycress from the Upper Midwest and Northern Great Plains, including relationships between pollinator visitation and site‐specific landscape, weather, and climatic variables.…”