The ecological causes and adaptive consequences of social behaviors in forked fungus beetles (Bolitotherus cornutus)

Classical behavioral ecology theory expects the distribution of resources to drive the expression and evolution of a wide range of social behaviors. One comprehensive way to describe social behaviors is with social networks, which capture the set of social interactions among all individuals within a population. My dissertation work explored how resource distribution influences social networks and their evolution by employing a large-scale manipulation of shelf fungus distribution in experimental populations of a mycophagous beetle (Bolitotherus cornutus). My results demonstrate that resource distribution only subtly impacts social networks, despite dramatic changes in patterns of space use. When fungus shelves are clumped, beetles reduce their home range size, which causes beetles to interact more often and with more partners. However, changes along other behavioral axes cause beetles to interact less often in environments with clumped resources. These opposing and simultaneous behavioral responses to different resource distributions produce limited effects on social networks. Despite these limited effects, resource distribution modulates sex-specific patterns of multilevel selection on social networks. The strength of selection on individual network position in males and group network structure in females increases in environments with clumped fungus shelves. Overall, my dissertation work establishes that social networks do not always capture behavioral changes across resource distributions and highlights the importance of applying a multilevel selection framework across ecological contexts to understand the evolution of social networks.