-Networks with a prescribed power-law scaling in the spectrum of the graph Laplacian can be generated by evolutionary optimization. The Laplacian spectrum encodes the dynamical behavior of many important processes. Here, the networks are evolved to exhibit subdiffusive dynamics. Under the additional constraint of degree-regularity, the evolved networks display an abundance of symmetric motifs arranged into loops and long linear segments. Exploiting results from algebraic graph theory on symmetric networks, we find the underlying backbone structures and how they contribute to the spectrum. The resulting coarse-grained networks provide an intuitive view of how the anomalous diffusive properties can be realized in the evolved structures.Introduction. -Networks have become a principal tool for the modeling of complex systems in a broad range of scientific fields [1][2][3]. In a dynamical network the topology describes the couplings between individual units of a dynamical process [4]. The general underlying question of research on dynamical networks is how the network structure shapes the global dynamical behavior.An important class of processes on networks are Laplacian dynamics in which the graph Laplacian is the operator of the (linearized) time evolution. The Laplacian spectrum and eigenvectors then describe the overall dynamical behavior. This class comprises many physical processes such as dynamics of Gaussian spring polymers [5], transport processes [6], random walks [7], and synchronization of oscillators [8][9][10].Another dynamical aspect is the evolution of network structure. Many systems change their connectivity structure in the course of time which affects the global dynamical behavior. The time scales of these two processes are often well separated with fast dynamics and slowly responding structural evolution. As an example, think of changes in neuronal activity in a brain on the one hand and the formation of synaptic connections on the other hand. In the opposite case, when dynamics and evolution happen on similar time scales one speaks of coevolutionary or adaptive networks [11]. Since the functionality of a system is often closely associated with dynamical behavior evolutionary forces will drive an evolving dynamical network towards some optimized structure.The method of network evolution adopts this strategy