Chapter 13: Dominance Systems

Dominance Systems explores the structural geometry of these social hierarchies, ranging from simple despotism, where one individual rules over all subordinates, to linear peck orders and complex networks containing triangular or circular elements. The text traces the historical evolution of the dominance concept, moving from early studies on bumblebees and domestic fowl to complex primate interactions, while distinguishing between absolute hierarchies and relative dominance based on spatial location. A significant portion of the chapter examines the evolutionary function of rank, contrasting individual selection with colony-level selection in social insects like Polistes wasps, where dominance behavior may regulate the division of labor rather than purely selfish reproductive success. Key behavioral properties are detailed, including the xenophobia principle which unifies groups against strangers, the role of control animals in maintaining peace, social inertia, and the phenomenon of nested hierarchies. The summary explains the tangible correlations between high status and genetic fitness, illustrating how dominant individuals secure priority access to food, nesting sites, and mates, as seen in examples ranging from wood pigeons and piglet teat orders to elephant seals. Conversely, the text investigates the compensatory strategies of subordinates, such as emigration, the potential for kin selection benefits (the spinster hypothesis), and the patience required in age-graded male systems. Finally, the chapter analyzes the biological and environmental determinants of rank, including size, hormones, and maternal lineage, while utilizing mathematical models like the Landau index to measure hierarchy strength and discussing aggressive scaling, where territorial behavior shifts toward dominance orders under high population density.