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Open Access item Pollinators foraging modifies nectar sugar composition in Helleborus foetidus (Ranunculaceae): an experimental test1
Herrera, Carlos M.
García, Isabel M.
|Keywords:||bumblebees, Helleborus foetidus, nectar sugar composition, nectarivorous yeasts, pollinator visitation, Ranun- culaceae, Spain|
|Publisher:||Botanical Society of America|
|Citation:||American Journal of Botany 95(3): 315–320. 2008|
|Abstract:||We experimentally tested the hypothesis that the extensive within-plant variation of nectar sugar composition in Helleborus foetidus (Ranunculaceae) and other species results from differences between flowers and nectaries in pollinator visitation history. Experiments were conducted to mimic single-nectary visits by wild-caught individuals of the main bee pollinators of H. foetidus, which were assayed for their capacity to modify the sugar composition of natural and artificial nectar. Experimental nectar probing with bee mouthparts induced extensive changes in proportional sugar composition 48 h after treatment, and bee taxa differed widely in their effects. Nectar probing by Andrena, medium-sized Anthophoridae, Apis mellifera, and Lasioglossum had no subse- quent effects on nectar sugar composition, while probing by Bombus terrestris and B. pratorum induced an extensive reduction in percentage sucrose, a marked increase in percentage fructose, and a slight increase in percentage glucose. Results support the hypothesis that stochastic variations among flowers or nectaries in the taxonomic identity of recent visitors and their relative visita- tion frequencies may eventually generate very small-scale mosaics in nectar sugar composition. Changes in nectar sugar composi- tion following bumblebee probing may be the consequence of nectar contamination with pollinator-borne nectarivorous yeasts|
|Publisher version (URL):||http://www.amjbot.org/content/95/3/315.full.pdf+html|
|Appears in Collections:||(EBD) Artículos|
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