Distribution of aphid clonal lineages per ant mound. Data are shown for three root aphid species Geoica utricularia (top), Tetraneura ulmi (middle) and Forda marginata (bottom) in 2008. Large dotted circles refer to sampling locations (1–8 from left to right), whereas small filled circles refer to sampled ant mounds, with the number of aphids found in the mound indicated by numbers within circles. Colors indicate the proportion of aphids belonging to particular clonal multilocus genotypes (MLGs), whereas multilocus lineages (MLLs) that combine closely related MLGs are identifiable by their similar color shades. Mounds with bold black margins were resampled in 2009 and 2010.