An Evolutionary Psychological Perspective of Indirect Aggression in Girls and Women

Although the effects of sexual selection on male mating competition and intrasexual aggression have been studied extensively for well over a century, female mating competition and intrasexual aggression have only begun to receive serious attention in recent decades. Here, we focus on one aspect of sexually selected competition in girls and women—rival derogation, which takes the form of indirect aggression. We argue that this tactic of intrasexual competition both reduces a rival’s ability to compete for desirable mates and helps aggressors achieve and maintain their own high social status. We further argue that physical attractiveness initiates the pathway leading to high social status, which is preserved through the use of indirect aggression and is associated with increased dating and sexual behavior.

Sex Differences in Mortality Rates Have Increased in China Following the Single-Child Law

Male behavior and physiology is designed for enhanced competitiveness at the expense of longevity, resulting in higher mortality rates compared to females in most species. These differences vary across populations consistent with factors indicating the intensity of male mating competition. Reproductive dynamics are strongly influenced by the relative proportions of potentially reproductive males and females in a population. Because the reproductive strategies of men and women are somewhat divergent, market influences on the intensity of mating competition and selectivity for partners produce different outcomes in female biased and male biased populations. The single-child law implemented in China in 1979 has led to increasing proportions of men in the Chinese population. Using historical mortality data, we found a trend for increasing sex differences in Chinese mortality rates from 1982 to 2000. This increase was most prevalent in young adulthood, when male mating competition is most intense as males reach sexual maturity and seek female partners. In contrast, males exhibited more survival gains than females in infancy and early childhood.

GENETIC VARIATION AND GENETIC LOAD DUE TO THE MALE REPRODUCTIVE COMPONENT OF FITNESS IN DROSOPHILA

ABSTRACT The genetic variation and genetic load due to virility, the male reproductive component of fitness, was measured in Drosophila melanogaster and D. pseudoobscura using males homozygous and heterozygous for the second chromosome of each species. Virility was determined in a female-choice, male mating competition experiment where both mating propensity and fertility were taken into account.——The mean virility of the homozygous D. melanogaster males relative to the heterozygous males was 0.50; the relative mean virility of the quasinormal homozygotes was 0.56. The mean virility of the homozygous D. pseudoobscura males relative to the heterozygous males was 0.70; the relative mean virility of the nonsterile homozygotes was 0.72, and of the quasinormal homozygotes, 0.68.——Depending on the species and chromosome sampled, fertile homozygous males had a mean virility 15 to 50% lower than the mean viability of individuals homozygous for a chromosome with quasinormal viability. The genetic load due to virility was also greater than that due to the female reproductive component. This higher level of hidden genetic variation (or genetic load) indicates that the results of PROUT(1971a, b) and BUNDGAARD and CHRISTIANSEN(1972), where the virility component of fitness dominated the dynamics of an artificial polymorphism, may be more general and that virility may dominate the dynamics of natural polymorphisms as well.