PARENT SESSION
Symposium #21: Effects of inbreeding and loss of genetic diversity on interactions with natural enemies.
Organized by: CT Ivey, DE Carr, and MD Eubanks
Wednesday, August 7. 1:00 PM to 4:30 PM. Crystal Ballroom, TCC.
Inbreeding and the loss of genetic variation: population genetics meets population interactions.
Carr, David*,1, 1 University of Virginia, Boyce, VA
ABSTRACT- Biotic interactions have long been considered important factors in determining the distribution and abundance of interacting species. Empirical studies have documented that for many of these interactions (host-parasite and plant-herbivore interactions, in particular) the genotypes of interacting species can play an important role in mediating their short-term (ecological) and long-term (evolutionary) outcomes. Historically, consideration of genetic changes within interacting populations has focused on adaptive changes resulting from the selective pressures generated (often reciprocally) by the interactions (e.g., the "Red Queen" hypothesis). Only recently have studies begun to examine how non-adaptive genetic change produced by inbreeding and drift might alter the outcome of these ecological interactions. Given the current interest in the biology of small populations and of metapopulations as well as the causes and effects of mating-system evolution in plants and animals, studies intended to expand our understanding of the consequences of non-adaptive genetic change for ecological interactions seem long overdue. For example, our recent studies on the yellow monkey flower, Mimulus guttatus, have demonstrated that inbreeding does not change susceptibility to a generalist pathogen (Cucumber mosaic virus) but inbred plants are much less tolerant of infection. In studies of plant-pollinator mutualisms in M. guttatus we have found that Bombus impatiens are significantly less likely to visit flowers of plants that are inbred. I will compare our results with Mimulus with other recent studies that have addressed the effects of inbreeding and outbreeding on population interactions and suggest potentially fertile directions for future research.
KEY WORDS: inbreeding, genetic diversity, plant-pathogen interactions, biotic interactions