PARENT SESSION
Thursday, August 10, 1:30-5:00 pm
COS 93 - Plant reproductive ecology
Plantation Room, Cook Convention Center
Presiders: B Molano and R Spigler
Effects of floral display on male and female reproductive success in Mimulus ringens.
Mitchell, Randall*,1, Karron, Jeffrey2, 1 University of Akron, Akron, OH, USA2 University of Wisconsin-Milwaukee, Milwaukee, WI, USA
ABSTRACT- The number of flowers blooming simultaneously on a plant may have profound consequences for reproductive success, affecting the potential for self pollination, pollen receipt, and pollen export. We used a novel experimental system to evaluate how these conflicting factors affect success through male and female functions. In this system we manipulated monkeyflower ( Mimulus ringens) floral displays in replicate (cloned) populations consisting of individuals with distinct multilocus genotypes that facilitate unambiguous measures of paternity and individual selfing rates. Genetic analysis confirms that larger displays both mother and sire more seeds, but that siring success per flower declines sharply with increasing display size. Female success per flower did not vary with display. Selfing rates from the maternal perspective increased with display, from 22.8% for 2 flowered displays to 37.8% for 16 flower displays. There was a much stronger increase in selfing rates from the male perspective, from 8% to 40%. Total fitness (accounting for the changes in selfing rate and observed levels of inbreeding depression) nonetheless increased strongly (but less than proportionally) with floral display. However, the marginal return on an additional flower steadily declined with display. Therefore a plant could maximize fitness by producing many small daily displays over a long flowering window rather than a few large displays over a brief flowering period.
Key words: Plant reproductive ecology, Pollination and paternity, Angiosperms / Phrymaceae / Mimulus