Life-history strategy defends against disease and may select against physiological resistance
Article first published online: 8 MAY 2013
© 2013 The Authors. Ecology and Evolution Published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Ecology and Evolution
Volume 3, Issue 6, pages 1741–1750, June 2013
How to Cite
Ecology and Evolution 2013; 3(6): 1741–1750
- Issue published online: 12 JUN 2013
- Article first published online: 8 MAY 2013
- Manuscript Accepted: 27 MAR 2013
- Manuscript Revised: 24 MAR 2013
- Manuscript Received: 28 NOV 2012
- NSF. Grant Number: DEB-0747222
- disease resistance;
- Microbotryum ;
Host ecological traits may limit exposure to infectious disease, thereby generating the wide variation in disease incidence observed between host populations or species. The exclusion of disease by ecological traits may then allow selection to act against physiological defenses when they are costly to maintain in the absence of disease. This study investigates ecological resistance in the Silene-Microbotryum pathosystem. An estimated 80% of perennial Silene species host the anther-smut disease while no annuals harbor the disease in nature. Artificial inoculations of annual and perennial Silene plants, obtained from both natural and horticultural populations, demonstrate that the absence of disease in annuals is not explained by elevated physiological resistance. The annual habit is thus a powerful form of ecological defense against anther smut. Moreover, the higher susceptibility of annual species to anther smut relative to perennials supports the hypothesis of a loss of costly physiological resistance under ecological protection. The observation in annuals that physiological susceptibility is correlated with lower rates of flowering (i.e., lower fitness) suggests that variation in physiological resistance is costly in the absence of disease, even in a naїve Silene species. The absence of disease in natural populations of annuals combined with their high physiological susceptibility attest to the strength of host ecology in shaping the distribution of disease and to the dynamic nature of disease resistance.