Just in time for Valentine’s Day, the introduction to my (foster) father’s 1991 Animal Behavior treatise, On the Role of Males (don’t worry guys, we get to expurgate genetic errors):
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.
Protracted demonstrations of competitive vigor are common in males, especially so in polygynous species. Darwin (1874) outlined in detail the virtual ubiquity of male aggressive “pugnacity” in animals, concluding that “It is incredible that all this should be purposeless” (1874, p. 615). The hypotheses to be argued here are threefold: (1) males are an auxiliary, relatively sacrificial sex of enhanced fragility, whose demonstrations of competitive vigor operate to expose, exaggerate, and expurgate significant gene error from the germline, (2) the aggressively competitive behavior of polygynous males is but one component of a hierarchy of genetic information assurance mechanisms that must be inevitably evolved, and (3) gene defect expurgation from the germline greatly accelerates the evolutionary optimization, and thus the competitiveness, of the species.