Date of Award

4-19-2013

Document Type

Thesis open access

Abstract

Colorful ornaments such as the pattern of a butterfly wing or the plumage of a peacock’s tail are among the most stunning products of evolution. Color, and the behaviors during which color is advertised, have come to serve important signaling functions for many species. Because color is often influenced by ecological factors such as diet or parasite load, the quality of an individual’s ornamental color can serve as an honest indicator of aspects of advertiser condition. For this thesis, I have investigated the potential for ornamental coloration and display behavior to serve as honest indicators of male quality as determined by ectoparasite load and body condition in three species of Caribbean Anolis lizards. Male lizards of these species possess dewlaps, brightly colored throat fans extended for use during behavioral interactions such as courtship or territory defense. I conducted two studies in the Dominican Republic in which I performed focal behavioral observations, quantified dewlap coloration using spectrometry, and estimated the ectoparasite loads and body conditions of lizards. In the first study, I examined individual variation in the red-orange dewlap coloration and display behavior among a population of Anolis brevirostris lizards, and found that individuals with more parasites exhibited dewlaps of higher brightness, were of lower body condition, and performed fewer dewlap displays than did individuals with fewer parasites. In the second study, I examined variation in dewlap color and display behavior in populations of Anolis cybotes and Anolis distichus lizards distributed at different elevations across two mountain chains. I observed that ectoparasite load differed between mountain chains, and that dewlap color increased with elevation for both species on both chains. Because measures of male quality were associated with aspects of color and behavior, the potential remains for dewlap color and display behavior to serve as honest indicators of male quality.

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