We’ve expanded Avida’s capacity for handling complex landscapes. In this, organisms (orange blocks) face a central-place foraging task. Organisms must be on the central ‘nest’ in order to reproduce. However, they must feed from one of the other food resources first. Thus, organisms must evolve to use and respond to ‘sight’ sensors for finding food. To limit the effectiveness of ‘fixed’ movement strategies, the food resources orbit at fixed distances (but in randomized directions) the central nest. The jagged edges of the food resource plateaus reflect resource consumption by the organisms. In this case, the organisms have evolved a preference for the more rewarding outer resources.
Example path of an Avida organism evolved to travel from a central birth nest (center circle, as in the environment above but without gradients) out to distant food resources and return home to reproduce. The organism’s outbound path is shown in black, while the inbound path (after feeding from the third resource) is white. Each of the five available food resources move in independent orbits, and each of their cumulative travel paths are shown here (colored bands). While the organism can evolve to look for and process information about the food resource it targets, the central nest is not detectable from afar. Consequently, return paths represent evolved strategies of fixed (patterned) search, random search, or compensation for detected spatial displacement (e.g., step retracing or path integration) using memory.