Monday, August 4, 2008: 1:30 PM
101 B, Midwest Airlines Center
Background/Question/Methods
Selection varies in time and space, and this has often been attributed to local or temporal differences in interactions with other organisms. The strength of selection in a population is likely to depend on the local intensity of interactions, but this is little studied. With computer simulations and a large empirical data set on the herb Primula farinosa and its biotic interactions, we examined the relationship between interactions intensity and selection strength on floral display traits.
Selection varies in time and space, and this has often been attributed to local or temporal differences in interactions with other organisms. The strength of selection in a population is likely to depend on the local intensity of interactions, but this is little studied. With computer simulations and a large empirical data set on the herb Primula farinosa and its biotic interactions, we examined the relationship between interactions intensity and selection strength on floral display traits.
Results/Conclusions
Both simulations and empirical data suggested that selection strength increased with decreasing intensity of interactions with pollinators and with increasing intensity of interactions with antagonists (a seed predator and grazers). The results indicate that relationships were curvilinear because of saturation of receptive stigmas at high pollination levels and depletion of the seed resource at high intensities of seed predation and herbivory. Knowledge about the form of the relationships between interaction intensity and selection strength should be crucial for predictions of how species and populations will respond evolutionary to a changing biotic environment.