Research worker Arjen Biere Problem definition Aim of this project is to gain insight into the evolution of active and passive disease-resistance mechanisms. In our studies of Silene alba , we find both quantitative resistance and avoidance mechanisms against the anther smut fungus Microbotryum violaceum .
Populations are polymorphic for both traits.
Costs and alternative explanations are considered experimentally and theoretically. Oviposition on infected plants resulted in a severe reduction of the infective potential in the population because developing caterpillars consumed a large proportion of the flower buds before fungal spores could be released from the anthers. This could affect the rate at which resistant genotypes can spread in a population. However, field studies suggest that the occurrence of the observed effects in the field will be limited since moths show a strong oviposition preference for uninfected flowers. Analyses will give insight in both the optimality of the oviposition decisions for the moth, and in consequences for spread of the disease and potential effects on the rate of spread of resistant genotypes in a population.