Dobson, Heidi .
How do newly-emerged specialist bees recognize their host flowers?
When pollen-specialist solitary bees emerge from their natal nests, they immediately recognize their host flowers when given a choice of different plant species; the floral cues used in this process are not well documented. In one bee species, Chelostoma florisomne (Megachilidae), which collects pollen exclusively from buttercups (Ranunculus), the females rely on the color and pollen odor of their host flowers. In a closely related species, C. rapunculi, which is a specialist on bellflowers (Campanula spp.), the cues used by the bees have been more difficult to elucidate. When bees were tested in multiple-choice experiments where they were offered different colors or flower odors, they showed no preference for Campanula. In a subsequent series of four experiments, where visual and olfactory cues of fresh flowers were tested alone and in combination by enclosing the flowers in glass vials with and without holes, both male and female bees again failed to recognize Campanula when given visual or olfactory stimuli alone, but showed some preference when these cues were offered together, and completely preferred Campanula when the flowers were unconcealed. The findings suggest that the cues are synergistic in the beesí recognition of their host flowers, and that the bees need to freely approach the flowers and thereby detect a gradient in floral odors, including odors from the nectar and pollen.
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1 - Whitman College, Department of Biology, 345 Boyer Ave., Walla Walla, Washington, 99362, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Wednesday, July 30th, 2008
Time: 4:15 PM