  $\beta$-cells are biologically essential for humans and other vertebrates.
Because their functionality arises from cell-cell interactions, they are also a
model system for collective organization among cells. There are currently two
contradictory pictures of this organization: the hub-cell idea pointing at
leaders who coordinate the others, and the electrophysiological theory
describing all cells as equal. We use new data and computational modeling to
reconcile these pictures. We find via a network representation of interacting
$\beta$-cells that leaders emerge naturally (confirming the hub-cell idea), yet
all cells can take the hub role following a perturbation (in line with
electrophysiology). A useful network representation of complex systems is via
pairwise cross-correlations between a system's constituents. Recently, attempts
have been made at representing pancreatic $\beta$-cells collectives as
networks, giving birth to the concept of hub cells, which contradicts
established electrophysiological theory. Here, we reconcile the hub-cell idea
with electrophysiology using empirical and computational methods. While the
former reveals the functional importance of hubs, the latter show that hubs are
an emergent property of communication among identical peers. Thus, individual
cells are perfectly capable of playing the hub role, but in line with
electrophysiology, they do not have to be genetically predisposed to do so.
This points to an ultra-robust architecture of $\beta$-cell collectives and
underpins some of their vital features.
