dominance hierarchy. This is also true in the species Polistes instabilis, where the next queen is selected based on age rather than size. Polistes exclamans also exhibits this type of hierarchy. Within the dominance hierarchies of the Polistes versicolor, however, the dominant-subordinate context in the yellow paper wasps is directly related to the exchange of food. Future foundresses within the nest compete over the shared resources of nourishment, such as protein. Unequal nourishment is often what leads to the size differences that result in dominant-subordinate position rankings. Therefore, if during the winter aggregate, the female is able to obtain greater access to food, the female could thus reach a dominant position. In some species, especially in ants, more than one queen can be found in the same colony, a condition called polygyny. In this case, another advantage of maintaining a hierarchy is to prolong the colony lifespan. The top ranked individuals may die or lose fertility and "extra queens" may benefit from starting a colony in the same site or nest. This advantage is critical in some ecological contexts, such as in situations where nesting sites are limited or dispersal of individuals is risky due to high rates of predation. This polygynous behavior has also been observed in some eusocial bees such as Schwarziana quadripunctata. In this species, multiple queens of varying sizes are present. The larger, physogastric, queens typically control the nest, though a "dwarf" queen will take its place in the case of a premature death. Variations Spectrum of social systems Dominance hierarchies emerge as a result of intersexual and intrasexual selection within groups, where competition between individuals results in differential access to resources and mating opportunities. This can be mapped across a spectrum of social organization ranging from egalitarian to despotic, varying across multiple dimensions of cooperation and competition in between. Conflict can be resolved in multiple ways, including aggression, tolerance, and avoidance. These are produced by social decision-making, described in the "relational model" created by the zoologist Frans De Waal. In systems where competition between and within the sexes is low, social behaviour gravitates towards tolerance and egalitarianism, such as that found in woolley spider monkeys. In despotic systems where competition is high, one or two members are dominant while all other members of the living group are equally submissive, as seen in Japanese and rhesus macaques, leopard geckos, dwarf hamsters, gorillas, the cichlid Neolamprologus pulcher,