Aggressive behavior across ant lineages: importance, quantification, and associations with trait evolution

Aggressive behavior, or lack thereof, is vital to the success of a social insect colony. A diversity of aggressive behaviors are exhibited in varying degrees by workers across ant species. To better understand this suite of behaviors, we review the extensive literature around ant aggression in order to assess the importance of aggression to the success of ant lineages, the ways in which aggression has been quantified in the literature, and potential correlations between aggression and other key functional traits. Our new contributions to this body of literature include an interaction framework for contextualizing the variation of behaviors, a new suggested scale for quantifying aggressive behaviors, and finally an investigation into traits that are correlated with aggression across ant lineages. Based on our phylogenetic comparative analyses, we find a negative correlation between eye length and aggression and that body size, worker polymorphism, and potentially participation in mutualisms with plants and other insects are evolutionarily linked to an increase in aggressive behavior.