Why some social systems form groups composed of kin, while others do not, has gone largely untreated in the literature. Using an individual-based simulation model, we explore the demographic consequences of making kinship a criterion in group formation. We find that systems where social groups consist of one-generation breeding associations may face a serious trade-off between degree of altruism and group size that is largely mediated by their kin composition. On the one hand, restricting groups to close kin allows the evolution of highly altruistic behaviors but may limit group size to suboptimal levels, the more severely so the smaller the intrinsic fecundity of the species and the stricter the kin admission rule. Group size requirements, on the other hand, can be met by admitting nonkin into groups, but not without limiting the degree of altruism that can evolve. As a solution to this conundrum, we show that if helping roles within groups are assigned through a lottery rather than being genetically determined, maximum degrees of altruism can evolve in groups of nonrelatives of any size. Such a "lottery" mechanism may explain reproductive and helping patterns in organisms as varied as the cellular slime molds, pleometrotic ants, and Galapagos hawks.

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To commemorate its declaration of a global khilafah in 2014, the Islamic State (IS) began publishing an online magazine, Dabiq, which became one of its primary recruiting tools during its rise to infamy. By using rhetoric that recalls U.S. presidential war rhetoric, specifically, tropes of “justice” and “time,” the English-language version of Dabiq fulfilled both subversive and hegemonic functions. It disrupted the reductive discourse that equates Islamic terrorists only with barbaric aggression and rendered IS as a rational global actor. Through this subversive move, IS aligned its anti-imperial interests with potential recruits in English-speaking Western countries with similar proclivities. At the same time, through its use of dominant Western war tropes, IS made a hegemonic attempt to facilitate recruits’ cultural identification so they assume a congruence of interests with IS, leading to an alignment of motives. Dabiq thus fulfilled an imperial trajectory through (neo)imperial rhetorics of identification and control. IS’s strategic use of (neo)imperial tropes in English—language of the empire—in Dabiq hence complicates monolithic (and Oriental) perceptions of the relationship between empire, imperialism, and Islamic terrorism in contemporary global political discourse. In addition, the significance of (neo) imperial tropes expands the heuristic scope of the rhetoric of terrorism by highlighting the implications of imperial ambitions and use of (neo)imperial rhetoric for the rise of global Islamic terrorism.

Using an individual-based and genetically explicit simulation model, we explore the evolution of sociality within a population-ecology and nonlinear-dynamics framework. Assuming that individual fitness is a unimodal function of group size and that cooperation may carry a relative fitness cost, we consider the evolution of one-generation breeding associations among nonrelatives. We explore how parameters such as the intrinsic rate of growth and group and global carrying capacities may influence social evolution and how social evolution may, in turn, influence and be influenced by emerging group-level and population-wide dynamics. We find that group living and cooperation evolve under a wide range of parameter values, even when cooperation is costly and the interactions can be defined as altruistic. Greater levels of cooperation, however, did evolve when cooperation carried a low or no relative fitness cost. Larger group carrying capacities allowed the evolution of larger groups but also resulted in lower cooperative tendencies. When the intrinsic rate of growth was not too small and control of the global population size was density dependent, the evolution of large cooperative tendencies resulted in dynamically unstable groups and populations. These results are consistent with the existence and typical group sizes of organisms ranging from the pleometrotic ants to the colonial birds and the global population outbreaks and crashes characteristic of organisms such as the migratory locusts and the tree-killing bark beetles.

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