Term of Award
Master of Science in Biology (M.S.)
Document Type and Release Option
Thesis (open access)
Copyright Statement / License for Reuse
This work is licensed under a Creative Commons Attribution 4.0 License.
Department of Biology
Committee Member 1
Committee Member 2
Condition-dependent signals can be used by conspecifics to obtain information on an individuals’ quality such as health, fighting ability, or immunocompetence. Variation in the severity of parasitic infections could mediate the differential expression of sexual signals in distinct populations of the same species. This could create diverse condition-dependent relationships between signals and quality. In this study, I examine the relationship between male signal expression and quality of Sceloporus woodi that inhabit areas with distinct ectoparasitic pressures. First, I examined if the brightness or size of male signals is indicative of body size or body condition in males without ectoparasites. Second, I used S. woodi from habitats with heightened parasite pressure to evaluate if brightness or size of male signals is indicative of the male qualities of body size or body condition. Third, I tested whether ectoparasite load is a predictor of signal brightness or size as predicted by the good genes and immunocompetence handicap hypotheses. Males without mites were caught only in the early breeding season and exhibited a negative correlation between the brightness of the black throat border and body size, suggesting that there may be seasonal trends and tradeoffs mediating this relationship. Males with mites were captured during the middle to late breeding season and displayed no correlations between size or brightness of badges and quality (body size or body condition). Thus, body size and/or body condition may not be ecologically important for male-male competition or female mate choice during the later breeding season. The brightness of the blue throat badge was not related to body size, body condition, or mite load, and likely serves as a signal for sex identity. Males with moderate mite loads had the darkest, most fully expressed abdomen badges indicating that the abdomen badge may be a signal of immunocompetence and ability to tolerate heightened parasitic pressure, providing partial support towards the good genes and immunocompetence handicap hypotheses. My findings reveal that each signal in male S. woodi likely provide information on ecologically and seasonally relevant traits, supporting the multiple messages hypothesis.
Roberts, Katherine M., "Male Color Badges Advertise Multiple Messages: Tradeoffs Among Color Badge Intensity, Size, and Ectoparasite Load" (2022). Electronic Theses and Dissertations. 2495.
Research Data and Supplementary Material