Shattering the folklore: black flies do not pollinate sweet lowbush blueberry

It is often said that on the Canadian Shield, black flies pollinate the swe et lowbush blueberry, because years with high black fly populations also te nd to be those with large blueberry crops. This folklore has never been tes ted experimentally. Here we report on research designed to test whether or not black flies can act as pollinators for two species of ericaceous plants , sweet lowbush blueberry (Vaccinium angustifolium) and leatherleaf (Chamae daphne calyculata). In enclosures, black flies may assist in leatherleaf po llination but there is no evidence that they increase fruit set in sweet lo wbush blueberry. However, we do not exclude the possibility that in the wil d, they act as opportunistic nectar thieves of sweet lowbush blueberry.