Relationships matter: How the social environment affects individual fitness-related behaviors

Individual behaviors related to fitness-enhancing events, like foraging and reproduction, are often shaped by internal and external factors. Of these factors, an individuals’ social environment has a dynamic effect on their behavior and this is particularly true for different types of social relationships. For example, affiliative interactions can increase an individuals’ sense of social security and improve their health, while agonistic interactions can lead to competition that alter an individuals’ access to resources. Social network analysis allows for the quantification of an individuals’ social relationships to examine whether specific aspects of sociality, such as number of social partners or centrality to a group, affect an individuals’ behavior. Social relationships do not have uniform effects across species and social systems and therefore, likely influence fitness-enhancing events in different ways. Here, I examine how an individuals’ social environment influences three important behaviors: their personality, how they solve problems, and how they may learn. In Chapter 2, I use bivariate Bayesian models to examine the co-variance between an individuals’ social network position in both their affiliative and agonistic networks and two consistent measures of anti-predator behavior: boldness, a measure of risk-taking, and docility, a measure of defensive aggression. I found that docile individuals were less involved in their agonistic network but that docility had no correlation with affiliative behavior. Boldness was not influenced by social environment. Overall, social environment impacts different anti-predator behaviors in different ways and in marmots, aggressive relationships are more important to anti-predator behavior than affiliative ones. In Chapter 3, I used structural equation models to examine how social network position indirectly affects a suite of behaviors used to solve a novel foraging problem. I found that marmots who used a diversity of behaviors were more successful problem-solvers and those who received aggression were less so. Social position indirectly impacted problem-solving success by altering the behaviors used when attempting to solve the box. Individuals who received high aggression were less persistent, less behaviorally diverse and less behaviorally selective. Thus, an individuals’ aggressive social environment alters how they approach a novel problem. In Chapter 4, I used generalized linear mixed effects models and network-based diffusion analysis to examine whether individuals learned and whether they socially transmitted foraging information on location or foraging skills. Not all yellow-bellied marmots learned to solve a novel foraging task or became more efficient at solving it with experience. While some colonies did socially transmit information on food location, they rarely socially transmitted motor skills associated with solving the foraging task. Overall, marmots are not extractive foragers and do not need to have the skills to solve complex foraging problems, but like other rodents, attract one another to locations of food. Together, these studies illustrate the value of studying social relationships using modern social network statistics