Before revision:  In contrast, under increased degree assortativity , Poisson networks can maintain high levels of cooperation, even exceeding those of scale-free networks, when the initial placement of cooperators is perfectly correlated to node degree. When the correlation is not perfect however, defectors placed within clusters of cooperators can act as Trojan horses, allowing defection to invade.
After revision:  In contrast, under increased degree assortativity , but will only do so under certain conditions. The effect depends nontrivially on the combination of the social network structure (degree distribution and assortativity), the type of social dilemma, and the presence of Trojan horses, i.e. defectors placed within clusters of cooperators can act as Trojan horses, allowing defection to invade.