Circadian Robot Metamorphosis

Insects, fish, and amphibians undergo the intriguing process of metamorphosis. Metamorphic processes are governed by gene regulatory networks: complex networks of gene-protein interactions. Recent studies demonstrate the isolated use of artificial gene regulatory networks for (1) body development, (2) metamorphosis, or (3) epigenetics. We will evolve a gene regulatory network by fitness uniform selection in such a way that a process of metamorphosis becomes coupled to a circadian rhythm of day and night. A fitness figure is established that defines the difference in average body size as a distinguishing metric to enforce a metamorphic process. Our results show that a swarm of modular robots can be evolved that shows a pronounced di erence in average body size during day versus night. Additional experiments show (1) robustness against virtual gene knockouts, (2) robustness against phase shifts, and (3) duty cycle adjustments of the circadian input. One of our conclusions is that light can provide epigenetic information for the process of metamorphosis.