MEYERS, J.J.; IRSCHICK, D.; VANHOOYDONCK, B.*; HERREL, A.; Tulane University; Tulane University; University of Antwerp; University of Antwerp: Divergent roles for different color signals in a polygynous lizard: A test of the reinforcement and dual-function hypotheses

Males of many animal species possess multiple colorful and elaborate sexual signals which are used to signal rival males, females, and potential predators. In this study, we examine the link between multiple sexual signals (throat patch and belly patch) and performance capacity in order to test whether multiple signals reinforce (reinforcement hypothesis) or provide differing (dual function hypothesis) information on male quality. We examined these relationships in the lizard Urosaurus ornatus, which exhibits a well-studied set of male morphs that are distinguished by dewlap coloration. Prior studies have shown that aggresive behavior in some morphs (blue dewlapped) make them dominant over other morphs, yet differences in morph performance capacity have not been documented. To examine the relationship between male morphs, sexual signals, and performance we captured 167 male U. ornatus at a riparian site in Northern Arizona. We measured external morphology, bite performance, maximum sprint speed and the area of the sexual signals (dewlap and belly patch). We found that the five morphs at our site (yellow-blue, orange-blue, blue, yellow, orange) did not differ in morphology, bite force or maximum sprint speed. Additionally, neither bite force nor maximum sprint speed was correlated with the area of the dewlap. Thus, dewlaps are not indicative of performance capacity but may relay information about behavioral traits such as aggression. In contrast to dewlaps, belly patch size was a significant indicator of increased bite force ability. Our findings support the dual function hypothesis of sexual signals in U. ornatus, and reveals that during display behaviors multiple aspects of male performance and/or quality are being communicated.