GEOMETRY FOR A SELFISH FORAGING GROUP - A GENETIC ALGORITHM APPROACH

The advantages of group living are not shared equally among all group members, and these advantages may depend on the spatial position occup ied by a forager within the group. For instance, it is thought that so cially dominant individuals prefer the predator-safe central position of groups forcing subordinates to the periphery. Uneven spread of bene fits among group members can occur when some animals (the scroungers) parasitically exploit the food findings of other foragers (the produce rs). Here ave focus on how playing producer or scrounger affects an in dividual's spatial position within a group. We model the movement of f oraging animals playing scrounger or producer using a spatially explic it simulation, and use a genetic algorithm to establish movement rules . We find that groups containing producers and scroungers are more com pact compared to an equivalent group of producers only. Furthermore, t he position occupied by strategies varies: scroungers are mainly found in central positions, with producers in the periphery, suggesting tha t the best position for strategies differs. Dominants, therefore, shou ld prefer movement rules which lead to central positions because of th e positional benefits provided to the scrounger strategy they use. Mor eover, position within a group will introduce an asymmetry among other wise phenotypically symmetric individuals.