A Mobile Ad-hoc NETwork (MANET) is an infrastructure less network that make possible to the mobile nodes to communicate with each other. But in the mobile ad-hoc networks, it is very complicated to accomplish energy efficiency and communication cost. In this paper, Gaussian Firefly algorithm based Unilateral Wakeup scheme (GFUW) is introduced to improve the energy efficiency. In this paper, the best path is selected by utilizing the concept of Gaussian firefly algorithm. The firefly optimization algorithm is used to identify the best transmission range over the networks.