The European honey bee (Apis mellifera) is native to parts of the Europe, North Africa and the Middle East and through domestication is found in other geographic regions, including the United States. Honey bees are experiencing declines across parts of the globe for reasons not yet completely understood but that appear to be related to disease and anthropogenic factors. Honey bees are artificially inseminated and shipped across country lines, which may exacerbate disease transmission across sub-species and geographic regions. We rely on honey bees for the pollination of most fruits and some vegetables, yet data suggests that the demand for their pollination services may no longer be met in the near future as crop needs rise, food-security becomes more problematic, and honey bees die. Quantitative data on alternative pollinator systems is valuable today. Mason bees (Osmia lignaria) are native to North America. In this study, four strawberry farms in Virginia were each split into two plots. On the experimental plots, mason bee cocoons were added. On the control plots, nothing was done (no mason bees were added). Mason bees fly about the distance of a football field, so cocoon additions were made on treatment plots >100 yards in length so bees were not likely to pollinate control plot flowers. At the time that mason bee cocoons were deployed, strawberry flowers that were still closed (backside of petals facing outward, reproductive parts unexposed) were marked with small zip-ties on their stems. In 30 days, berries were picked from the experimental and control plots and weighed to the nearest 0.01g.
Results/Conclusions:
A two factor ANOVA demonstrates an effect of treatment (or mason bee addition, F=10.21, p=0.000) and farm (F=14.18, p=0.00), but no farm by treatment interaction (F=0.115, p=0.891). The lack of interaction occurs since all farms had similar increases in berry weight, on the mason bee addition plot, relative to the control plot. The mean increase in berry weight on experimental plots was ~20%. Economic data for Virginia from 2017 indicates that this translates into about an additional 50 cents per pound in berry value. Further work improving our knowledge regarding pollination services provided by additional native bees found in agricultural ecosystems is warranted since we need solutions for the impending climate-change related food security issues that we face, in addition to solutions that provide valued pollinator services while honey bees experience declines related to disease and anthropogenic effects.