Behavioral and morphological traits interact to promote the evolution of alternative reproductive tactics in a lizard

Alternative reproductive tactics (ARTs) are predicted to be the result of disruptive correlational selection on suites of morphological, physiological and behavioral traits. ARTs are most obvious when they occur in discrete morphs with concomitant behavioral tactics. However, ARTs driven by behavior, in species lacking obvious phenotypic differences, are rarely documented and poorly understood. We quantified selection acting on phenotypic traits predicted to characterize ARTs by observing marked lizards in six semi-natural populations. We quantified reproductive fitness for each male using 6 microsatellite DNA loci from 226 offspring born to 56 females. Candidate models containing directional and correlational selection gradients were equally supported. As predicted, large males with large home ranges and large males who were observed frequently had the highest reproductive success. We also found evidence that large males that moved little, but were observed frequently and large males w...