Texas wintergrass (Nassella leucotricha), a common rangeland grass, is frequently infected by a fungus (Atkinsonella texensis) that sterilizes the plant. Infected plants, however, may grow faster and be more likely to survive than uninfected plants. This study will determine whether this is true, by testing three different hypotheses: (a) The fungus may directly cause infected plants to grow faster and be more likely to survive. (b) Infected plants may recover from being eaten by insects better than uninfected plants, perhaps because they are larger. (c) Infection may make a plant less likely to be eaten by insects, perhaps because the fungus produces distasteful chemicals. This study will also test whether fungal infection affects a plant's ability to compete with other plants for light, water, and nutrients. Although fungi probably play very important roles in natural ecosystems, their roles are poorly known; this study will help fill this gap.
