Intralocus sexual conflict over human height

Abstract

Intralocus sexual conflict (IASC) occurs when a trait under selection in one sex constrains the other sex from achieving its sex-specific fitness optimum. Selection pressures on body size often differ between the sexes across many species, including humans: among men individuals of average height enjoy the highest reproductive success, while shorter women have the highest reproductive success. Given its high heritability, IASC over human height is likely. Using data from sibling pairs from the Wisconsin Longitudinal Study, we present evidence for IASC over height: in shorter sibling pairs (relatively) more reproductive success (number of children) was obtained through the sister than through the brother of the sibling pair. By contrast, in average height sibling pairs most reproductive success was obtained through the brother relative to the sister. In conclusion, we show that IASC over a heritable, sexually dimorphic physical trait (human height) affects Darwinian fitness in a contemporary human population.

Does natural selection favour taller stature among the tallest people on earth?

“…Of course, there may be many other ecological differences between the United States and The Netherlands that may favour taller or shorter stature (see [3] for further discussion), and there is no reason to expect that selection pressures will be consistent across populations, or across time [51]. Furthermore, biases in sampling or response rates, and accuracy of reporting, also hinder accurate comparison between the two populations (see also [15]). …”

The Reproductive Ecology of Industrial Societies, Part I

“…Such biases may have serious implications for fertility research, in particular, and for the conclusions that can be drawn in an evolutionary framework. For example, studies have shown that men under-report pregnancies from previous relationships, and that previously married and unmarried men are less likely to be included in demographic samples, leading to sex differences in the number of reported children (Rendall et al 1999; Stulp et al 2012a; see Stulp et al 2016 for more examples). Another potential bias may arise through extra-pair paternity: men may not know they are the father of certain children, whereas other men may erroneously assign paternity to children who are not, in fact, their own.…”

Balancing Selection in Species with Separate Sexes: Insights from Fisher’s Geometric Model

“…Current estimates of sex-specific selection reveal widespread asymmetries in the strength or direction of selection on individual phenotypic traits (Cox and Calsbeek 2009;Stulp et al 2012), and recent estimates of multivariate selection from humans and two insect species provide concrete examples of sex differential selection within multivariate trait space [r sel -0.61 for three traits of the Indian meal moth (Lewis et al 2011), r sel -0.73 for seven traits in Drosophila serrata (Gosden et al 2012), and r sel 0.22 for seven traits in a human population (Stearns et al 2012)]. Although this set of studies is small, selection patterns are consistently divergent between the sexes, which implies that mutations with sexually antagonistic fitness effects should be common (Connallon and Clark 2014) and that sexual antagonism should play an important role in generating balancing selection (i.e., SA directional or SA mixed mechanisms, as shown here).…”