XVI International Botanical Congess

Sexual dimorphism in plant reproductive traits may result in sexual differences in susceptibility to attack by pest species such as herbivores and pathogens. This can have interesting consequences for the evolution of mating behavior of males and females in dioecious plant species. A case study is presented of differences in susceptibility between males and females of Silene latifolia (white campion) to the host sterilizing anther smut fungus Microbotryum violaceum. The fungus produces its spores in the flowers of its host plants and is transmitted by pollinating insects. Males have a higher probability of contracting the disease, but disease incidence in natural populations is usually unbiased or female biased. I use a detailed study of infection dynamics to resolve this apparent paradox, and summarize traits that possibly contribute to sexual differences in susceptibility.