Abstract
Consistent individual differences in behavior, i.e. animal personality, are often correlated within broader syndromes1 that can cause evolution in one trait to drive correlated changes in other behaviors via genetic correlations2. Despite abundant demonstration that these behavioral syndromes are common across taxa3,4, it has not been clear whether syndromes arise due to genetic and cellular mechanisms or because particular combinations of behavioral responses are favored. Here we show that populations of field crickets (Gryllus integer) exhibit a genetically conserved behavioral syndrome structure despite differences in average behaviors. We found that the distribution of genetic variation and covariance among behavioral traits was consistent with genes and cellular mechanisms underpinning behavioral syndromes rather than historic correlated selection. Moreover, divergence among populations’ average behaviors was constrained by the genetically conserved behavioral syndrome. By constraining the divergence of populations, animal personality may therefore also affect the ability of species to behaviorally diverge and therefore speciation. This suggests important ways in which labile traits—traits that are highly plastic, like behavior, physiology, and life-history traits—might affect evolutionary outcomes.