Controlling development and chemotaxis of soft-bodied multicellular animats with the same gene regulatory network

Abstract

The ability to actively forage for resources is one of the defin-ing properties of animals, and can be seen as a form of min-imal cognition. In this paper we model soft-bodied robots, or “animats”, which are able to swim in a simulated two-dimensional fluid environment toward food particles emit-ting a diffusive chemical signal. Both the multicellular de-velopment and behaviour of the animats are controlled by a gene regulatory network (GRN), which is encoded in a lin-ear genome. Coupled with the simulated physics, the activity of the GRN affects cell divisions and cell movements during development, as well as the expansion and contraction of fil-aments connecting the cells in the swimming adult body. The global motion that emerges from the dynamics of the animat relies on the spring-like filaments and drag forces created by the fluid. Our study shows that it is possible to evolve the animat’s genome (through mutations, duplications and dele-tions) to achieve directional motion in this environment. It also suggests that a “minimally cognitive ” behaviour of this kind can emerge without a central control or nervous system.