Do Bateman's principles extend to human societies?

Bateman’s work on fruit flies contributed strongly to the understanding of sexual selection mechanisms, as first mentioned by Charles Darwin. Bateman concluded from his experiments that males show a higher variance in reproductive success than females (Principle I), that males show a higher variance in mating success than females (Principle II) and that the relationship between reproductive success and mating success is stronger in males than in females (Principle III). Consequently, sexual selection pressure on traits that increase the probability of getting multiple mating partners will be higher in males than in females. The aim of this thesis is to investigate if Bateman’s principles extend to human societies as well. A distinction is made between populations with different mating systems (e.g. polygamous, or monogamous). Bateman’s principles were observed in several human populations, including modern Western populations. Nevertheless, Bateman’s first principle seems present to a greater extent in polygynous populations and, although little was known about variances in mating success and the relationship between reproductive success and mating success, this is also expected for the second and third principle. These findings highlight the opportunity for sexual selection mechanisms to work in human societies. However, several limitations, such as the fact that most databases about reproductive success and mating success are biased, should be taken into account when interpreting evidence found for Bateman’s principles in humans. Further research, for example with the addition of data about population density or sex ratio, is necessary to determine the differences in mating and reproductive behavior between the sexes and to see if these differences are to the same extent present in different human populations.