The Genetics of Sexual Selection in Nauphoeta Cinerea

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Most population genetic models assume that mating is random with respect to the character of interest. However mating is often nonrandom with respect to many characters that influence mating success. There is considerable evidence that success in male-male competition and/or female mate choice is a fairly common contributor to nonrandom mating in variety of species. As a result, there has been a growing attempt to generate genetic models of the process and effects of such selection. Unfortunately, the number of models has exceeded our empirical knowledge of this process, resulting in a growing call for studies that begin to test the predictions and assumptions contained in mathematical models. This study will begin to address this need by examining the genetics of secondary sexual characters, courtship pheromones, and sexual behavior in Nauphoeta cinerea. Empirical studies have been hampered by a lack of suitable model species. The cockroach N. cinerea has many attributes that facilitate genetic studies of sexual selection, including short generation time, facultative parthenogenesis, and well characterized behavior. These qualities permit a detailed examination of assumptions and predictions derived from theoretical studies. Variation in female mate choice, male social behavior, male attractiveness, and related male pheromones will be assessed by behavioral assays and gas chromatography. Genetic variances and convariances within and between the sexes will be estimated from a paternal half-sib mating design. Artificial selection based on male attractiveness to females will be used to confirm genetic estimates obtained from the breeding experiments. The information generated from this study will increase our general knowledge of the phenotypic and genetic structure of pheromones and chemical communication. In addition, this study will be sufficiently detailed to test several predictions and assumptions of mathematical models of sexual selection and the evolution of sexual dimorphism. Finally, these experiments will provide empirical data that bear on several issues in evolutionary genetics.