on a real robot, each subcontroller was evolved separately in an offline manner. Further, there is no evidence that there proposed architecture can be used across multi-robot scenarios in a decentralized manner. Moioli et al. [@moioli2008towards] proposed the GasNet system where subcontrollers for two different tasks were activated or inhibited based on the production and secretion of virtual hormones. Their homeostasis-inspired controller was able to select appropriate subcontrollers depending on internal and external stimuli.

Duarte et al. [@duarte2012hierarchical] portrays a search and rescue task using a real e-puck robot. The overall task was divided into a few subtasks and separate subcontrollers were evolved for each of them. The experimenter provided the fitness function for each subtask. After the appropriate subcontrollers were found, a behaviour arbitrator was evolved which delegates a subtask to the best subcontroller based on the sensory inputs. Though a complex task was solved using their hierarchical controller, the behaviour primitives and the behaviour arbitrator do not seem to have been evolved in an online and on-board manner. A similar line of work by Duarte et al. [@duarte2014hybrid] also demonstrates an approach for the incremental transfer of their evolved hierarchical control system from simulation to real robots. Of 