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Pollen foraging by bumblebees: Foraging patterns and efficiency onLupinus polyphyllus

✍ Scribed by Jared Haynes; Michael Mesler


Book ID
104755822
Publisher
Springer-Verlag
Year
1984
Tongue
English
Weight
551 KB
Volume
61
Category
Article
ISSN
0029-8549

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✦ Synopsis


Bumblebees foraging on vertical inflorescences start near the bottom and work upward, behavior commonly interpreted as a response to the greater amounts of nectar available in lower flowers. Lupinus polyphyllus, which produces no nectar, has more pollen available in upper flowers. Although bees are probably unable to detect this gradient, since pollen is hidden from their view, they still start low and forage upward. Therefore, we concluded that the bees' tendency to forage upward on vertical inflorescences is not tied to a reward gradient. In addition, bees use only about 15% of the flowers per inflorescence, although they could be much more efficient by visiting and revisiting every flower systematically. In general, revisits would not be penalized because most flowers contain enough pollen for several visits. Optimal foraging theory may not offer an adequate explanation for such gross inefficiency.