Pollination of commercial northern highbush blueberry fields is often achieved through rented colonies of the managed honey bee, Apis mellifera. Recommendations for blueberry pollination emphasize hive stocking density, or number of hives per acre, for growers to meet their pollination needs. However, the strength of these colonies may also contribute to pollination success. Measuring Apis mellifera colony strength is expected to provide growers, who depend on strong colonies for sufficient crop pollination, a more accurate estimate of the number of foragers available for pollination services. In this thesis, I report a study to investigate the influence of honey bee colony number, size, and activity on honey bee density in the field and pollination success in commercial highbush blueberry systems of the cultivar 'Bluecrop'. During 2021 and 2022, honey bee density in blueberry fields was not influenced by stocking density, but there was a positive relationship between farm-level colony strength and honey bee density in the field. Honey bee density in the field was a significant predictor of the seed number per berry and the estimated partial yield. I also compared the standard cluster count method for colony size estimation to two non-invasive methods: counting the number of foragers returning to hives and measuring the thermal signature of the same colonies using a hand-held infrared camera. Returning forager counts at colony entrances were positively correlated with colony cluster counts in both years. There was no relationship between infrared sampling and the other methods in 2021, whereas a positive correlation was found in 2022. My results indicate that colony strength, which can be effectively measured using non-invasive methods, is an important indicator of farm-level honey bee density, which can be used to predict pollination success in blueberry farms.
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