  Adaptive dynamical networks appear in various real-word systems. One of the
simplest phenomenological models for investigating basic properties of adaptive
networks is the system of coupled phase oscillators with adaptive couplings. In
this paper, we investigate the dynamics of this system. We extend recent
results on the appearance of hierarchical frequency-multi-clusters by
investigating the effect of the time-scale separation. We show that the slow
adaptation in comparison with the fast phase dynamics is necessary for the
emergence of the multi-clusters and their stability. Additionally, we study the
role of double antipodal clusters, which appear to be unstable for all
considered parameter values. We show that such states can be observed for a
relatively long time, i.e., they are metastable. A geometrical explanation for
such an effect is based on the emergence of a heteroclinic orbit.

Adaptation and Self-Organizing Systems;Pattern Formation and Solitons