Mitchell, Randall , Karron, Jeffrey .
Influence of pollinator visitation patterns on multiple paternity in Mimulus ringens.
Animal-pollinated Angiosperms cannot directly control gamete receipt or export. Instead, these plants depend on movements of pollinators whose foraging behaviors often fail to optimize the quantity or quality of pollen deposited on stigmas. Furthermore, the stochastic nature of pollinator visits often leads to striking among-flower differences in mating patterns. One factor likely to contribute to this among-flower variation is the timing and composition of sequential pollen loads deposited on each stigma. Each pollen load may differ markedly in sire representation, especially if successive pollinators approach a flower from distinct compass directions and carry pollen from different donors. Although pollen deposited during an initial floral visit may have a siring advantage due to priority, pollen grains deposited during later visits may also compete successfully for access to ovules. This multiple mating is likely to increase the genetic diversity in a sibship, which may influence competitive interactions among developing seeds within fruits and among seedlings in the field. We experimentally tested the hypothesis that sequential pollinator visits contribute to the exceptionally high levels of multiple paternity in fruits of Mimulus ringens (Phrymaceae), a wetland perennial native to North America. We documented all bee visits to individual flowers, quantified resulting seed set, and determined paternity for 20 seeds per fruit. Most (76%) flowers received multiple visits, and the interval between visits was usually < 30 min. Flowers visited multiple times produced 44% more seeds than flowers visited once. All fruits were multiply sired. Flowers receiving a single visit averaged 3.12 outcross sires per fruit, indicating that single visits deposit pollen from several donors. Multiple paternity was even greater following three or more visits (4.92 outcross sires), demonstrating that sequential visits bring pollen from donors not represented in the initial visit.
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1 - UNIVERSITY OF AKRON, Department Of Biology, Department Of Biology, AKRON, OH, 44325-3908, USA
2 - University Of Wisconsin-Milwaukee, Department Of Biological Sciences, PO BOX 413, MILWAUKEE, WI, 53201, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Waterman Room/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:00 PM