Analysis of Pollination Services Provided by Wild and Managed Bees (Apoidea) in Wild Blueberry (Vaccinium angustifolium Aiton) Production in Maine, USA, with a Literature Review

Sara L Bushmann,Francis A Drummond

doi:10.3390/agronomy10091413

Abstract

Maine is the largest producer of wild blueberry (Vaccinium angustifolium Aiton) in the United States. Pollination comes from combinations of honey bees (Apis mellifera (L.)), commercial bumble bees (Bombus impatiens Cresson), and wild bees. This study addresses (1) previous research addressing wild-blueberry pollination, (2) effects of wild-bee and honey-bee activity densities on fruit set, yield, and crop value, (3) the economic value of wild-bee communities, and (4) economic consequences of pollinator loss. Bee communities were sampled in 40 fields over three years (2010–2012) and bee activity densities were estimated for bumble bees, honey bees, and other wild bees. These data were applied to an economic model to estimate the value of bee taxa. Bumble bees and honey bees predicted fruit set and reduced its spatial heterogeneity. Other wild bees were not significant predictors of fruit set. Yield was predicted by fruit set and field size, but not pest management tactics. Our analysis showed that disruption in supply of honey bees would result in nearly a 30% decrease in crop yield, buffered in part by wild bees that provide “background” levels of pollination. Honey-bee stocking density and, thus, the activity density of honey bees was greater in larger fields, but not for wild bees. Therefore, a decrease in crop yield would be greater than 30% for large fields due to the proportionally greater investment in honey bees in large fields and a relatively lower contribution by wild bees.

Highlights

Lowbush blueberry (Ericaceae: Vaccinium angustifolium Aiton), the dominant plant in the wild blueberry species complex, contributes prominently to Maine’s economy
When considering 2011 and 2012 fields for these two years, we found a positive relationship between numbers of honey bee hives in fields and honey-bee activity density with 27% of the variation in honey bee foraging explained by the model (F(1,26) = 9.532, p = 0.005, r2 = 0.27)
If the coefficient of variation (CV) of fruit set was used as a predictor variable, we found it to be a significant predictor of yield (F(1,12410) = 8.577, p = 0.003) and, crop value

Summary

Introduction

Lowbush blueberry (Ericaceae: Vaccinium angustifolium Aiton), the dominant plant in the wild blueberry species complex (see Appendix A), contributes prominently to Maine’s economy. Maine is the largest producer of wild blueberry in the United States [1], a crop that, from 2012–2018, averaged. Wild blueberry is primarily an outcrossing native North American fruit crop that relies on insects to vector pollen from one clone (genetically unique individual plant) to another [4]. Bees are the primary pollinators of wild blueberry (see Appendix A). Bushmann and Drummond [5] documented more than 120 bee species associated with wild-blueberry fields. This is approximately 43% of the total 278 bee species recorded in Maine [6]. On the basis of a single bee flower visit, bumble-bee queens (Bombus) are the most efficient pollinator of wild blueberry, followed in efficiency by bees of the genera Andrena and

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Conclusion