The western honey bee, Apis mellifera L., is recognized as the most commercially important pollinator in agriculture worldwide. However, the importance of A. mellifera as pollinators in natural systems is a matter of debate, despite the fact that it has been introduced to many ecosystems worldwide.
We performed a meta-analysis of plant-pollinator interaction networks from 73 localities to examine the numerical importance of A. mellifera in natural ecosystems worldwide. Where possible, we obtained quantitative pairwise interaction networks from the literature or from study authors. Using each network as a replicate, we calculated the worldwide average proportion of floral visits contributed by A. mellifera. We also examined the distribution of A. mellifera visits across plant species to quantify the proportion of plant species that may be reliant on A. mellifera for pollination.
Apis mellifera was present in 52 of the 73 localities, and where it is present, visited nearly 30% of studied plant species (mean = 38%) and accounted for an average of 18% of the total visits. Apis mellifera contributed the most floral visits among all recorded pollinator species in 14 out of 52 networks. While A. mellifera contribute few or no visits to the majority of the studied plant species, it accounted for >50% of the visits for 203 out of 1320 (15.4%) plant species examined. Given the anticipated trends of wild pollinator declines, it is crucial to understand the contributions of this ubiquitous and numerically important species to the pollination of natural ecosystems worldwide.