GLMMs in action: gene-by-environment interaction in total fruit production of wild populations of Arabidopsis thaliana

摘要: Spatial variation in nutrient availability and herbivory is likely to cause population differentiation and maintain genetic diversity in plant populations. Here we measure the extent to which mouse-ear cress (Arabidopsis thaliana) exhibits population and genotypic variation in their responses to these important environmental factors. We are particularly interested in whether these populations exhibit nutrient mediated compensation, where higher nutrient levels allow individuals to better tolerate herbivory. We use GLMMs to estimate the effect of nutrient levels on tolerance to herbivory in Arabidopsis thaliana (fixed effects), and the extent to which populations vary in their responses (variance components) 1. Below we follow guidelines from Bolker et al.(2009, Fig. 1, Box 4) to step deliberately through the process of model building and analysis. In this example, we use the lme4 package (Bates and Maechler, 2010) in the R language and environment (R Development Core Team, 2009)[][version 2.11. 1]