Recent Topics Posters
Tamez, Claudia A. , Davelos Baines, Anita , McDonald, Andrew .
Factors Governing Pollinator Parasitism in a South Texas Water Lily (Nymphaea elegans).
While theoreticians believe that mutualistic relationships often evolve from parasitic relationships, the opposite has apparently occurred in the water lily family (Nymphaeaceae). Phylogenetic analyses of the Nymphaeaceae indicate that the peculiar parasitic relationship between members of Nymphaea and their pollinators is a derived trait, having descended from mutualistic, entomophilous pollination systems, such as Cabomba, Nuphar, and Victoria. Nymphaea flowers offer pollen rewards to bees and flies, yet divest their visitors of pollen loads by trapping them within a pool of stigmatic fluid produced within their cup-shaped ovaries. Pollinators frequently drown inside this pool of ‘nectar,’ thereby relinquishing most of their pollen loads. Obviously, this behavior would be counterproductive if lethality events were obligate, so most flowers merely detain their pollen-laden visitors for a brief period of time. We conducted a study on a native South Texas water lily, Nymphaea elegans, during two flowering seasons in order to analyze factors that govern pollinator mortality rates in this plant species. We analyzed the size variation of flowers, ovaries, and nectar volumes in order to test the influence of these factors on insect mortality. We find that nectar volumes correlate positively with ovary size; and we demonstrate statistically that flowers with large nectar volumes are more lethal than those with small volumes. This relationship likely accounts for the lack of pollinator mortality in neighboring populations of Nymphaea mexicana, as this species produces very small ovaries and nectar volumes. Our results identify the sexual advantages of producing large flowers and lay ground for future studies on the disadvantages of producing massive flowers, which would theoretically eliminate pollinator populations.
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1 - University of Texas Pan-American, Biology, 1201 West University Drive, Edinburg, Texas, 78541, USA
2 - University of Texas Pan American, Biology, 1201 West University Drive, Edinburg, TX, 78541, USA
University of Texas Pan-American
Presentation Type: Recent Topics Poster
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM