It is increasingly common to see multiple wireless networks existing in the same environment, being accessed by devices of the individual networks as well as by ``hybrid'' devices capable of communicating on multiple networks. Typically these networks do not cooperate or share resources, resulting in sub-optimal network performances. The efficiency of such networks can be increased by exploiting hybrid nodes to enable network interactions that allow cross-network performance optimizations and cross-network information and service sharing. Such mutually beneficial interactions of the networks is referred to as symbiotic networking. In this paper, we investigate the potential performance gains of such interactions for the routing protocols and the effect of the network parameters on these potential gains. We use both simulation and mathematical frameworks that model the routing performances of both symbiotic and independent networking to quantify the routing benefits of symbiotic networking. Our results show that symbiotic networking can provide vital support to co-located networks, which is especially important in resource-constrained networks such as wireless sensor networks or mobile ad hoc networks.