This tuning fork was used for all the artificial hand pollination treatments. It vibrates at the same frequency as a bumble bee’s wings during buzz pollination (a 128 C).
Bumble bees pollinate tomatoes and many other agricultural plants, providing great economic value; approximately 3 billion dollars annually for U.S. agriculture. Unfortunately, declines in multiple bumble bee species across North American have been observed and habitat loss remains a staggering problem for populations.
Commercial greenhouse tomato pollination is often done by artificially "buzzing" tomato flowers to increase self-pollination, but a pilot study suggests this treatment produced smaller fruit when compared to natural bumble bee buzz pollination. I investigated the question: how important is cross-pollination by bumble bees to fruit production and plant reproductive success in tomatoes? At the UW Farm’s Center for Urban Horticulture location, I treated 24 tomato plants (Solanaceae sp.) with two self-pollination methods (natural selfing and artificial hand-"buzzed" selfing) and two cross-pollination methods (natural bumblebee cross-pollination and artificial hand-"buzzed" crossing).
I measured volume and seed number per fruit, as well as percent germination of seeds produced from each treatment. Percent germination was highest in the hand-"buzzed" cross-pollination treatment, suggesting that bumble bees may introduce variables that reduce seed viability (such as disease). Nevertheless, I found that cross-pollination by bumblebees resulted in the highest volume and greatest number of seeds per fruit over all other methods of pollination. These results provide clear support for the value of the ecosystem services bumble bees provide. Larger fruit represents more food and can be sold for a higher market value, while more seeds provide a fitness increase for the tomato plant. Conservation and agricultural policies and practices should be reviewed to promote healthy bumblebee populations.
If you would like to learn more about what you can do to improve bumble bee habitat in your neighborhood please check out the recommendation page on my website.