Average number of interactions as a function of the degree of the vertex for different types of random heterogenous population structures:

<p>(A) Erdós-Rényi random graphs <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003567#pcbi.1003567-Erds1" target="_blank">[<b>53</b>]</a>, (B) Newman-Watts small-world networks <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003567#pcbi.1003567-Newman1" target="_blank">[54]</a>. (C) Barabási-Albert scale-free networks <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003567#pcbi.1003567-Barabsi1" target="_blank">[42]</a>, and (D) Klemm-Eguiluz highly-clustered scale-free networks <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003567#pcbi.1003567-Klemm1" target="_blank">[55]</a>. All graphs have size and an average degree of . At each time step a randomly chosen individual interacts with a randomly selected neighbour. The average number of interactions is shown for simulations (blue dots) and an analytical approximation for graphs where the degrees of adjacent vertices are uncorrelated (red line, see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003567#pcbi.1003567.e137" target="_blank">Eq. (8)</a>).