Trait elaboration via adaptive mate choice: sexual conflict in the evolution of signals of male quality

Honest advertisement models of sexual selection have been widely discussed as hypotheses for the evolution of ornament traits but, as previously formulated, these models lack a mechanism for the elaboration of display characters. I propose that female demand for display characters that reliably signal male quality leads to selection for male strategies to express these display characters independent of quality. The result can be an evolutionary race leading to the elaboration of male characters while maintaining a correlation between character expression and male quality. Extreme elaboration of display traits will occur only if males are able to adopt strategies that reduce the cost of character expression; otherwise, simple or moderately elaborated traits can remain reliable indicators of male quality indefinitely. Several display traits such as pheromone signals and carotenoid pigmentation of the integument are often found with associated structures that may have evolved through sexual conflict of interest.