Spiders provide some ideal model species to study the contribution of these factors to successful range expansions. Many spiders are efficient long‐distance dispersers. By passive wind‐mediated dispersal on silk threads, so called ballooning, they are capable of moving large distances in a single generation (Foelix 2010). They can thus quickly follow changing environmental conditions as evidenced by several ongoing poleward range expansions (Hänggi and Bolzern 2006; Muster et al. 2008; Kumschick et al. 2011). Recent work also shows that such range expansion can be accompanied and facilitated by rapid adaptive divergence of expanding lineages (Krehenwinkel and Tautz 2013). Spiders are also subject to intense parasitism by hymenopterans and dipterans. By causing more than 50% mortality in some populations, these parasites may impose strong selection (Finch 2005). A reduction of parasite load in novel environments could then result in rapid population growth.