Crants, James , Rathcke, Beverly .
Do habitat edges and coflowering species facilitate the pollination of a plant with nectarless flowers?
MAYAPPLE (Podophyllum peltatum L.), an Eastern North American forest understory herb, depends on outcross pollination by insects for sexual reproduction. However, its flowers lack nectar, and it consequently has very low visitation rates and pollination success. Visitation rates and pollination success for unrewarding entomophilous species are often promoted by proximity to rewarding plants, and similar facilitation effects may apply to anything that increases the local abundance of pollinators. In this study, we tested whether pollination for mayapple was facilitated by wild geranium (Geranium maculatum L.), a co-flowering, nectar-producing species, and by forest edges, which are expected to be favorable habitats for both pollinators and plant species that co-flower with mayapple. Pollen greatly limited mayapple's fruit and seed production. Pollinator visitation rates were extremely low, and mayapple colonies were highly self-incompatible. However, we found only weak evidence for facilitation of pollination by wild geranium based on seed set per flower, and none based on fruit set per flower or seed set per fruit. There was no evidence for facilitation of pollination by forest edges. Fruit and seed set were actually lower near edges, though this is not explained by a difference in pollination success. Facilitation of mayapple pollination by co-flowering plants may occur over spatial scales other than those used in this study, or it may be more likely in communities with greater density and diversity of rewarding flowers than those found in out study sites.
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1 - University of Michigan, Department of Ecology & Evolutionary Biology, 830 North University Avenue, Ann Arbor, Michigan, 48109-1048, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM