Figure 1 summarizes how we evaluate evolutionary processes occurring during range expansion. Specifically, an increase in reproductive output of individuals from the edge relative to the core supports selection at low densities as the dominant process, while decreased reproductive output of edge individuals supports expansion load or trade-offs as the dominant process (Fig. 1A). Increased dispersal among individuals from the edge indicates that spatial sorting is acting during this range expansion (Fig. 1B), while if dispersal does not change between core and edge, other factors, such as adaptation to the new environment, may be limiting the opportunity for spatial sorting. We also expect that individuals’ dispersal choices will be influenced by the contexts they experience, specifically density and mating status (Fig. 1B). If density-dependence has evolved during the range expansion, we predict that dispersal will be less positively or negatively density-dependent for mated individuals from the range edge (Fig. 1B, dashed line). We use a common garden to evaluate the patterns of evolution of early fecundity, age at first reproduction, body mass, and dispersal of eight populations of the biocontrol agent Diorhabda carinulata, collected from the core and edge of its range in the western US.