Biologically inspired designs can improve the design of artificial agents. In this paper we explain and explore the role of directional light sensors from an Evolutionary Robotics perspective using a dynamical systems approach. It was found that by using directionally specific sensors in the agent, there was a simplification of the neural controller employed. This simplification helped not only with the analysis of this type of controller but also improved the behavioural performance of the agents, thereby showing a good example of the ecological balance principle. Categories and Subject Descriptors I.2.9 [Artificial Intelligence]: Robotics Autonomous Vehicles; I.2.9 [Artificial Intelligence]: Robotics Sensors General Terms Design Keywords Evolutionary Robotics, Adaptive Behaviour, Evolution of Sensors