Parasites and female choice in the ring-necked pheasant.

Abstract

The Hamilton and Zuk hypothesis is based on several assumptions: 1) The parasites adversely affect host fitness, and susceptibility to parasites is heritable. 2) Expression of secondary sexual characteristics is, at least to some extent, dependent on host condition and vigor, and therefore on host ability to control parasites. 3) Females evolve appropriate discriminatory preference for secondary sexual characteristics that best reveal susceptibility to parasites. This paper presents the results of experiments designed to test these assumptions, using the Ring-necked Pheasant, Phasianus colchicus. The results show that resistance to disease can be heritable. Preliminary analysis of the mate choice tests does not reveal that these resistant offspring have better developed secondary sexual characters, or that females prefer them. However, there is a correlation between display rate; coccidian parasite load, and female choice in male pheasants.