Figure 1.

Graphical rendition of the territorial bargaining game as outlined by Maynard Smith (1982). In a 1D habitat, 2 adjacent individuals have territorial centers or nest sites located on the left (black) and right (gray) sides. Each territorial owner requires a core area, denoted by dashed lines, to obtain any fitness. Fitness increases incrementally with increasing distance from the core edge up to a point, beyond which there is no further benefit. The owners can each display a graded signal, indicating their valuation of a boundary location at different distances from the core. An honest signaler displays at the maximum level within its core, and beyond the core displays at a level corresponding to the importance of the place, that is, decreasing in intensity with an increasing distance from the edge of his core area. Two honest strategists compare their display levels at the same position, and if the opponent displays at a lower level, the focal animal advances, whereas if the opponent displays at a higher level, he retreats. The two then agree on a boundary at the point (downward arrow) where their display levels are the same, meaning that their motivations are equal. If the regions of interest do not extend into the opponent’s core area, for example, because the territorial centers are farther apart, a mixed ESS of Hawk and Bluffer occurs.