Date on Master's Thesis/Doctoral Dissertation


Document Type

Doctoral Dissertation

Degree Name

Ph. D.



Degree Program

Biology, PhD

Committee Chair

Eason, Perri

Committee Co-Chair (if applicable)

Alexander, James

Committee Member

Dugatkin, Lee

Committee Member

Pearson, William

Committee Member

Fuller, Rebecca

Author's Keywords

mate preference; Neotropical cichlid; carotenoids; vision; learning


This dissertation takes a comprehensive approach to the role of dietary carotenoids on redness and the subsequent behaviors in the firemouth cichlid, Thorichthys meeki. I start with a brief introduction into signaling, the importance of carotenoids, and mate choice. The dissertation is then divided into three data chapters which are designed to stand as independent manuscripts. Chapter II documents how altering the availability of dietary carotenoids affects redness in the integument of male and female T. meeki. I tracked how redness changed in color and distribution in individuals over the course of 12 weeks. I confirm that a dichotomy in redness can be obtained in this time period via diet alone. However, carotenoids are used by animals for more than red ornamentation including color vision. To account for this potential effect of carotenoids in my study animals, I examined if color vision was affected by the high- and low-carotenoid diet treatments (chapter III). Furthermore, I determined whether redness (a trait for which T. meeki is named) is innately attractive to this species (chapter III). The sensory bias hypothesis suggests that males and females utilize traits that are innately appealing to the opposite sex to attract a mate. My final data chapter examines whether males and females use redness and other visual displays as a signal in mate selection (chapter IV). I conclude this dissertation by summarizing my findings and proposing future directions in which I wish to examine this system further (chapter V).