Relative conspicuousness of threat display components in the Jacky dragon (Amphibolurus murcatus)

Selection for conspicuousness has been an important force on visual signal design. Although signal efficacy has been extensively studied in acoustic systems, few have examined this attribute in dynamic visual signals. We simulated signal competition in Jacky lizards (Amphibolurus muricatus) by presenting isolated motor patterns (tail-flick, push-up body rock, and slow arm wave) used in social communication. Experiment 1 used four digital video playback systems to present simultaneous display combination as on opposing monitors to a subject situated in the middle. Experiment 2 maintained the same design and display combinations, but tested signal conspicuousness across three levels of visual noise (calm, typical and windy) simulated by windblown vegetation. Jacky lizard motor patterns are designed to address distinct functional requirements: the most salient visual display is the tail flick that serves as an ideal alerting component, with high efficacy over a range of signaling conditions. This is followed by the push-up body rock, used in aggressive interactions, which has a more restricted range. The least salient is the submissive slow arm wave designed to appease nearby dominant males. This relationship is robust across environmental wind conditions. We detected no significant side biases, suggesting no lateralisation in perceptual processes.1 page(s