Social Capital in Coordination Experiments: Risk, Trust and Position

Social capital theory is exemplary in attempting to integrate both individual and institutional perspectives in the study of governance, but interactions between the individual and institutional components remain underexplored and unspecified in many situations. We extend the theory from its focal attention on prisoners dilemma games to an important and understudied class of collective action problems of critical concern for governance— coordination tasks ranging from simple matching games to more complex tasks involving conflict (battle of the sexes) and assurance problems (stag hunt). Laboratory experiments provide a means of observing the impact of institutional influences (bridging and bonding network capital), individual predispositions (trust and risk aversion), and their interaction on the ability to coordinate in these settings. The results confirm that neither individual nor institutional components alone can explain coordination, and that interactions between these components must be understood in terms of the specific task context being studied

Is Promiscuity Associated with Enhanced Selection on MHC-DQα in Mice (genus Peromyscus)?

Reproductive behavior may play an important role in shaping selection on Major Histocompatibility Complex (MHC) genes. For example, the number of sexual partners that an individual has may affect exposure to sexually transmitted pathogens, with more partners leading to greater exposure and, hence, potentially greater selection for variation at MHC loci. To explore this hypothesis, we examined the strength of selection on exon 2 of the MHC-DQα locus in two species of Peromyscus. While the California mouse (P. californicus) is characterized by lifetime social and genetic monogamy, the deer mouse (P. maniculatus) is socially and genetically promiscuous; consistent with these differences in mating behavior, the diversity of bacteria present within the reproductive tracts of females is significantly greater for P. maniculatus. To test the prediction that more reproductive partners and exposure to a greater range of sexually transmitted pathogens are associated with enhanced diversifying selection on genes responsible for immune function, we compared patterns and levels of diversity at the Class II MHC-DQα locus in sympatric populations of P. maniculatus and P. californicus. Using likelihood based analyses, we show that selection is enhanced in the promiscuous P. maniculatus. This study is the first to compare the strength of selection in wild sympatric rodents with known differences in pathogen milieu