Monitoring commercial seed fields: bee nests
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.