Honey bee stocking numbers and wild blueberry production in Nova Scotia

Eaton, L. J. and Nams, V. O. 2012. Honey bee stocking numbers and wild blueberry production in Nova Scotia. Can. J. Plant Sci. 92: 1305-1310. Wild blueberries ( Vaccinium angustifolium Ait.) require cross pollination by insects. Introduction of managed species such as honey bees (Apis mellifera L.) and alfalfa leafcutting bees (Megachile rotundata Fabr.) is costly. We assessed the effects of stocking rates of honey bee hives and the interacting effects of the numbers of honey bees and other bees on yield of blueberries in commercial fields. Blueberry fields were sampled from 101 fields in years 1991 to 2010 in Nova Scotia. We recorded field size, numbers of beehives, yield, densities of bees, numbers of buds, blossoms and set fruit. Yields increased linearly with numbers of beehives, up to similar to 4 hives/hectare, but at higher stocking rates there was too much variation to adequately determine the effects. Yields also increased linearly with numbers of honey bees, but there was an interaction with other bees that decreased the effects of honey bees, such that at maximum densities of other bees, there was no effect of honey bees on yield. These results suggest that other bees and honey bees compete for pollination. If producers have limited numbers of beehives, we suggest that more should be placed in areas where densities of other bees are lower, up to approximately 4 hives/hectare.