Data from a field experiment in which the dynamics of green peach aphid (Myzus persicae) populations consisting of one clone (non-evolving) were compared to the dynamics of populations consisting of two clones (potentially evolving). A total of three aphid clones were used, which were all tested individually and in each combination. At the start of the experiment, 20 third-instar individuals were placed on a caged host plant. For half of the populations, cages were removed at day 13, allowing competitors to access the plants. Rapid evolutionary responses were observed, which increased population growth rates by 33% to 42% compared to non-evolving populations. These results have been published in Turcotte, Reznick & Hare (Ecology Letters, 2011). Data have been reanalyzed to estimate which demographic rates were underlying different dynamics among clones, and between non-evolving and evolving populations, making use of changes in stage structure through time. These results have been published in Bruijning, Jongejans & Turcotte (Journal of Animal Ecology, forthcoming).