Proceedings of the Chiricahua Mountains Research Symposium Pine Canyon United Methodist Camp, Chiricahua Mountains, AZ March 16-17, 1992, pp. 123-126.   On the role of males Wirt Atmar The value of males to a species has often been regarded as enigmatic. An all-female, parthenogenetic population has significant theoretical advantages over a population that must reproduce sexually. But if sexuality is to be advocated as highly advantageous to the species, the questions surrounding gender differentiation must not be confused with the questions concerning the value of sex. Two distinct genders are not necessary to engage sexual recombination. A broad array of hypotheses for the evolution and persistence of sexuality appears in Michod & Levin (1988), yet for all of the postulated arguments, males are unnecessary. While purpose cannot always be easily ascribed to a specific trait or behavior, the converse can be argued with confidence. The widespread, common existence of a specific trait, behavior or caste insures that the persistence of the attribute possesses some fundamental purpose. Sustained, demonstrable vigor integrates an enormous amount of information across a broad and diverse range of qualities into a single, easily realized metric. It is at once a measure of the individual phenotype's sensory acuity, its capacity to avoid predation, its immune system compentancy, general intelligence, and foraging behavior. The prolonged demonstration of vigor in a sexually mature adult becomes a highly integrative measure of overall phenotypic quality, providing reasonable assurance that the individual phenotype is free of primary congenital defect. However the efficiency of the defect expurgation process from the germline does not need to be extreme to be effective. The effect is multiplicatively regenerative, generation after generation, honing species-specific variances to levels at or near environmental noise. There exists however a third attribute characteristic of the evolution of error reduction mechanism (repair and vigor demonstrations) that has been very little discussed. The exclusion of macromutational error from the germline dramatically accelerates the optimization of the phyletic lineage. (1.1MB)