A truly ecological epigenetics study.

Until a few years ago, epigenetics was a field of research that had nothing to do with ecology and that virtually no ecologist had ever heard of. This is now changing, as more and more ecologists learn about epigenetic processes and their potential ecological and evolutionary relevance, and a new research field of ecological epigenetics is beginning to take shape. One question that is particularly intriguing ecologists is to what extent epigenetic variation is an additional, and hitherto overlooked, source of natural variation in ecologically important traits. In this issue of Molecular Ecology, Herrera & Bazaga (2011) provide one of the first attempts to truly address this question in an ecological setting. They study variation of DNA methylation in a wild population of the rare, long-lived violet Viola cazorlensis, and they use these data to explore interrelations between environmental, genetic and epigenetic variation, and in particular the extent to which these factors are related to long-term differences in herbivore damage among plants. They find substantial epigenetic variation among plant individuals. Interestingly, this epigenetic variation is significantly correlated with long-term differences in herbivory, but only weakly with herbivory-related DNA sequence variation, which suggests that besides habitat, substrate and genetic variation, epigenetic variation may be an additional, and at least partly independent, factor influencing plant–herbivore interactions in the field. Although the study by Herrera & Bazaga (2011) raises at least as many new questions as it answers, it is a pioneering example of how epigenetics can be incorporated into ecological field studies, and it illustrates the value and potential novel insights to be gained from such efforts.