Evaluation of the Utility of Adding Artificial Bumble Bee Nesting Sites to Increase Pollination Services in a Small Farm Environment

View the project final report

• 2011 annual report
• 2012 annual report

Commodities

• Fruits: berries (other), berries (strawberries)
• Vegetables: beans, beets, cucurbits, eggplant, greens (leafy), onions, peppers, tomatoes
• Animals: bees

Practices

• Education and Training: on-farm/ranch research
• Natural Resources/Environment: biodiversity, habitat enhancement
• Production Systems: general crop production

A two-year trial to study the efficacy of providing artificial nest boxes to increase bumble bee abundances on farm sites was implemented in 2012 and 2013. None of the 300 nest boxes deployed over two years was occupied by bumble bees, regardless of insulation material, entrance type or orientation. The phenology of bee-visited crop blooms was tracked and compared to the phenology of bumble bee species in the area. Bumble bees active in June through August visited more crops than those active earlier in the season.

Introduction

With recent honey bee declines impacting managed pollination services, the vulnerability of American agriculture under the dominance of the honey bee has become increasingly apparent in recent years. Many American farms utilize managed honey bees for crop pollination services, yet dependence upon a single, non-native organism for such a crucial service is an unsustainable approach. Bumble bees are native pollinators that visit a wide variety of plant species and can pollinate many field crops such as berries, melons, cucumbers, etc (reviewed in Klein et al. 2007). Wild populations of native bumble bees freely provide indispensable pollination services which have been shown to surpass those of honey bees in many crops (e.g. watermelon, Winfree et al. 2008). However, in some agricultural systems, their pollination efficiency seems to be limited by their population size (e.g. pak choi, Rader et al. 2009). In order to be effective crop pollinators, bumble bees must not only be abundant enough to provide ample pollination services, but their seasonal cycles must also coincide with crop bloom periods. Bumble bee species exhibit a seasonal colony cycle, with some species appearing early in spring and declining by mid-summer, and others having the opposite cycle (Colla and Dumesh 2010). Clearly data on the seasonal abundances of regional bumble bee species could aid farmers seeking to improve native pollination services. One of the grassroots recommendations for enhancing bumble bee populations pollination services is adding artificial nest boxes to increase local populations (e.g. Mader et al. 2010). Reported occupancy rates of nest boxes vary widely, ranging from 0% to 67% occupancy, but the real utility of this method for attracting and maintaining bumble bees has not often been tested in the USA southeastern United States (Holm 1966; Donovan and Wier 1978; Delaplane and Mayer 2000). Our study aimed to develop recommendations for providing bumble bee nest boxes (hereafter, “boxes”) to increase native pollinator abundance and provide information on the timing of bumble bee abundances in relation to crop bloom to aid farmers in their ability to capitalize on native pollinators.

1. Evaluate the utility bumble bee nest boxes for increasing the prevalence of bumble bees on small, multi-crop farms 2. Determine if providing additional bumble bee nesting sites via artificial nesting boxes changes the species diversity and relative abundance of bumble bees 3. Determine the seasonal abundance of different bumble bee species as it relates to crop bloom times 4. Develop a set of recommendations for bumble bee nest boxes for farmers in Arkansas