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Monitoring commercial seed fields: bee nests

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Slide 19 of 21

The tradeoff is that when pollination is accomplished rapidly, the bees run out of resources sooner. As part of our monitoring project, we put straws in bee boards in each shelter at the beginning of the season, and when a bee had finished work on a nest in a straw, we removed it from the bee board, and brought it back to the lab. We x-rayed the straws to see what was inside, and we compared straws that were completed early in the season (third and fourth week after bee release) and straws that were completed late in the season (after the 4th week of the study). Early season nests were provisioned when flower standing crop is high, whereas late season nests were provisioned when standing crop was low. A number of variables relating to cells and nests are likely to be affected by flower resources. Number of cells per nest decreased significantly in all fields late in the season, as did percent of the nests that were incomplete, i.e., they had no nest cap, suggesting that they were abandoned before they could be completed. Pollen balls, which could be affected by nectar availability, and chalkbrood, which may be related to pollen quality, both decreased in 5 of the 7 fields studied.

For more information:

Strickler, K. and S. Freitas. 1999. Interactions between floral resources and bees in commercial alfalfa seed fields. Environ. Entomol. 28(2): 178-187.