Abstract Detail



Reproductive Processes

Karron, Jeffrey [1], Mitchell, Randall [2], Trapnell, Dorset [3], Christopher, Dorothy [4], Semski, Wendy [4], Devaux, Celine [5], Porcher, Emmanuelle [6].

Tradeoffs between selfing rate and siring success in monkeyflower.

One of the great unanswered questions in plant evolutionary biology is why intermediate selfing rates are common. This pattern in nature is not concordant with classical genetic models which predict that disruptive selection on selfing rate will cause mixed mating to be rare and transitory. Selfing is favored in populations with low inbreeding depression because more maternal alleles are transmitted through self-fertilized seeds than through outcross seeds. By contrast, outcrossing is favored in populations with high inbreeding depression because the transmission advantage of selfing is offset by the reduced fitness of selfed offspring.
Several models have explored a potential tradeoff between siring success and selfing. This tradeoff is known as “pollen discounting”, and may maintain stable mixed mating in conditions that would otherwise favor outcrossing. Empirical support for this tradeoff has been found in species with large floral displays and frequent pollinator movements among flowers on the same plant. Such pollinator movements increase geitonogamous self-pollination, but reduce pollen export. However, there is almost no empirical work exploring other mechanisms generating this tradeoff.  In particular, pollen discounting in single flowered plants has not been evaluated. Such pollen discounting would require that an increase in within-flower self-pollen deposition leads to a comparable reduction in the amount of pollen export to recipient plants in the population.
To quantify the tradeoff between selfing rate and siring success in the wild, we established experimental populations of the bumble bee-pollinated wetland perennial Mimulus ringens. This species has a mixed mating system with selfing rates typically between 20-65%.  Using unambiguous paternity assignment we are quantifying selfing rates and siring success of every individual in each of three replicate (cloned) populations.  Our novel experimental design will therefore provide unique insight into the genetic basis of key mating system parameters: individual selfing rates, siring success, and pollen discounting.  


1 - University Of Wisconsin-Milwaukee, Department Of Biological Sciences, Po Box 413, Milwaukee, WI, 53201, United States
2 - University Of Akron, Department Of Biology, Dept Of Biology, Akron, OH, 44325, United States
3 - University of Georgia, Plant Biology, 2502 Miller Plant Sciences, 120 Carlton St., Athens, GA, 30602, USA
4 - UW-Milwaukee, Dept of Bio Sci, P.O. Box 413, Milwaukee, Wisconsin, 53201-0413, United States
5 - University of Montpellier, ISEM, Montpellier, France
6 - MNHN, Ecology Center, 61 Rue Buffon, Paris, France

Keywords:
selfing rate
paternity
mating system
pollination.

Presentation Type: Oral Paper
Number:
Abstract ID:141
Candidate for Awards:None


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