P1.120 Jan. 4 The function of bright male coloration in the sunset spider, Frigga pratensis (Salticidae) TAYLOR, L. A.; Arizona State University Lisa.A.Taylor@asu.edu
Several jumping spiders (Salticidae) are sexually dichromatic – females are inconspicuous while males have vivid colors. Here, I test three hypotheses about the function of male coloration in the sunset spider (Frigga pratensis), in which females are cryptic, whereas males have a conspicuous red abdomen. The first hypothesis (‘female choice hypothesis’) proposes that, because males often engage in elaborate courtship displays, male colors may serve as honest signals to females of a male’s quality as a potential mate. The second hypothesis (‘male-male competition hypothesis’) proposes that, because males often guard and/or fight over access to females, bright colors may reliably signal fighting ability to rivals. The third hypothesis (‘mimicry hypothesis’) proposes that, due to increased mobility compared to females, males may have developed conspicuous coloration to mimic potentially dangerous organisms. I found no support for the female choice or male-male competition hypotheses. Specifically, while the intensity of male color was variable, aspects of coloration did not correlate with body condition, suggesting that color is unlikely to provide reliable information about a male’s quality as a mate or his fighting ability. Further, males did not overtly display their colorful abdomens to females during courtship or to other males during competitive interactions. My results are most consistent with the mimicry hypothesis. When clay spider models were placed on leaves in the field, those that were painted with the color pattern of male F. pratensis were attacked less often by predators than unpainted control models, suggesting that such coloration has the potential to deter predators.