Individual (co)variation of field behavior and locomotor performance in curly tailed lizards

Animal communication among competitors often relies on honest signaling such that displays of aggression accurately reflect an individual's performance abilities. Moreover, the maintenance of honest signaling should be enhanced by the existence of consistent individual differences in behavior and performance, and individual-level correlations between them. Despite this, researchers studying honest signaling rarely measure behavioral repeatability. Here, we demonstrate that field behaviors of free-ranging lizards and a measure of locomotor performance in the laboratory are consistent among individuals (i.e. they were repeatable), although the magnitude of repeatability varies among traits. In addition, endurance appears to be correlated with display frequency in the field at the individual level, suggesting that display frequency is an honest signal of endurance. Interestingly, this correlation was strong for males, and non-existent for females. Our results extend previous studies of behavior-performance relationships by identifying a sex-specific correlation between traits and by partitioning phenotypic correlations into between- and within-individual components. This analytical approach is emerging as a powerful tool for studying individual variation in behavior and physiology.