  The costs associated to the length of links impose unavoidable constraints to
the growth of natural and artificial transport networks. When future network
developments can not be predicted, building and maintenance costs require
competing minimization mechanisms, and can not be optimized simultaneously.
Hereby, we study the interplay of building and maintenance costs and its impact
on the growth of transportation networks through a non-equilibrium model of
network growth. We show cost balance is a sufficient ingredient for the
emergence of tradeoffs between the network's total length and transport
effciency, of optimal strategies of construction, and of power-law temporal
correlations in the growth history of the network. Analysis of empirical ant
transport networks in the framework of this model suggests different ant
species may adopt similar optimization strategies.
