Models of conflict and voluntary cooperation between individuals in non-egalitarian social groups

This thesis broadly investigates the evolution of voluntary cooperative behaviour among individuals in conflict in non-egalitarian social groups. This work is partitioned into three sections. In the first section, we explore the emergence of non-egalitarian social groups to better understand the evolutionary incentives for voluntary participation in groups with unequal distributions of resources. In the second section, we study several scenarios in which genetically related individuals with unequal control over resources cooperate despite being in conflict. The evolution of parent-offspring conflict over provisioning, offspring signals, and alloparental care are each addressed in this section. In the last section, we investigate cooperative behaviours between unrelated individuals in conflict by modelling the evolution of coalitionary behaviour

Excerpts from the Report of the Committee of Visitors

Admissions standards, building rehabilitation, and a national law schoo

Excerpts from the Report of the Committee of Visitors

Admissions standards, building rehabilitation, and a national law schoo

Data from: The influence of environmental variance on the evolution of signalling behavior

A recent meta-analysis has indicated that environmental quality and variability can influence whether offspring begging and parental responses to these signals are motivated by offspring need or offspring quality. We create a model to verify and apply evolutionary logic to this hypothesis. We determine the ecological and social conditions under which species signal and respond to need in favorable environments, and to quality in poor environments. The environmental conditions that favor this shift are widest when signalling costs and differences in quality between offspring are moderate. Low relatedness between siblings coupled with high signalling costs, as well as moderate relatedness between siblings coupled with low signalling costs, allow for the shift between signals of need and signals of quality to occur in more volatile environments. Further, only species whose offspring are highly dependent on parents for survival are not expected to use both signals of need and of quality. Ultimately, this shift between signalling need and signalling quality is the result of high-quality offspring benefiting more from meagre amounts of parental provisioning, while low-quality offspring have most to gain when parents can contribute more substantially. We show that this differential benefit of resources depends substantially upon offspring fitness as functions of parental investments, a variable which has lacked both diversity and biological realism in previous theoretical approaches. We then use this work to reassess previous theory on signals of need and of quality

Survival[Scramble]

Survival[Scramble

Rank[Scramble]

Rank[Scramble

Data from: Concessions, lifetime fitness consequences and the evolution of coalitionary behavior

The relationship between the costs of coalitionary behavior and the evolution of such behavior has not been closely examined by theoretical studies. Here, we create a set of life-history models for species whose coalitionary behavior is genetically determined to investigate how different types of costs afflicted upon members of failed coalitions, in terms of survival, fecundity, and social rank, may influence the nature of coalitionary behavior that emerges at evolutionary equilibrium. We also extend previous theory by examining the coevolution between coalitionary behavior and concessions granted by dominant individuals to prevent dominants from being targeted by coalitions. We show that species that form coalitions to contest social rank evolve to regularly form bridging coalitions under a vast majority of social and ecological settings, whereas species that contest fecundity form all-up coalitions under most conditions. Further, dominant individuals concede resources to subordinates to prevent coalitionary attacks only in very few circumstances, and these concessions occur only to ensure another individual is a more attractive coalition target. We compare and contrast results to empirical data to provide an evolutionary context for commonly observed coalitionary behaviors in the animal kingdom

Matlab Code

This Matlab script finds the minimum and maximum resources necessary in both good and poor environments necessary for the stability of the equilibrium of interest for a given set of parameter conditions. It plots the relevant region of stability