Individual forager profits in Apis mellifera unaffected by a range of colony Varroa destructor densities

Abstract

The parasitic mite Varroa destructor Anderson and Trueman negatively affects honey bee health, flight activity, and foraging behavior, all of which can be expected to affect foraging energetics. We tested this hypothesis in a 3-year field study. In each year, four-frame nucleus colonies with varying loads of varroa were placed under cages with mature rabbiteye blueberry plants, Vaccinium ashei. Individual bee weights consistently decreased as colony varroa populations increased, affirming that the design produced a range of colony mite effects. However, average forager flower handling times and nectar ingestion rates were unaffected by changes in colony varroa levels. Moreover, there were no significant effects of colony varroa levels on individual net foraging energy gain determined per flower, per second handling time, or per second total foraging time. We conclude that individual forager profits in Apis mellifera are unaffected by the range of colony V. destructor densities used in this study. These results are relevant to the question of the extent to which foraging of individuals relates to colony state in social Hymenoptera.