Human size evolution: no evolutionary allometric relationship between male and female stature.

In many animal groups, sexual size dimorphism tends to be more pronounced in species with large body size. Similarly, in a previous cross-cultural analysis, male and female stature in humans were shown to be positively allometrically related, indicating a similar relationship where populations with larger stature were more dimorphic. In this study, we re-examine the hypothesis of an allometric relationship between the sexes using phylogenetic methodology. First, however, we tested whether there exist phylogenetic signals in male and female stature. Data on mean stature from 124 human populations was gathered from the literature. A phylogenetic test showed that male and female stature were significantly associated with phylogeny. These results indicate that comparative methods that to some degree incorporate genetic relatedness between populations are crucial when analyzing human size evolution in a cross-cultural context. Further, neither non-phylogenetic nor phylogenetic analyses revealed any allometric relationship between male and female stature. Thus, we found no support for the idea that sexual dimorphism increases with increasing stature in humans.

Gustafsson A ，Lindenfors P 《journal of human evolution》

Latitudinal patterns in human stature and sexual stature dimorphism.

There exists substantial variation in human stature and sexual stature dimorphism that has been attributed to both genetic and environmental variables. A few studies have previously investigated possible relationships between latitude and stature, building on the idea that variation in climate can influence body size (Bergmann's rule). This change in body size can in turn have influenced sexual stature dimorphism (in accordance with Rensch's rule). The present study investigated whether latitude is associated with variation in human mean stature and sexual stature DIMORPHISM. Phylogenetic and non-phylogenetic analyses were conducted on a cross-cultural sample of 124 human populations. The results indicate that both male and female mean stature increase with increasing distance from the equator. While sexual stature dimorphism also was positively related to latitude in the non-phylogenetic test, this relationship disappeared when using a phylogenetic comparative method. Evidence was also found for curved relationships between latitude and both male and female stature, as well as stature dimorphism, all indicating a maximum at around 40 degrees from the equator. The results of the present study indicate that both male and female stature are weakly associated with latitude. It is possible that these relationships are evolved responses to variation in climate. No unequivocal conclusion could be drawn regarding a possible relationship between latitude and sexual stature dimorphism.

Gustafsson A ，Lindenfors P 《-》

Stature and sexual stature dimorphism in Sweden, from the 10th to the end of the 20th century.

Mean stature in a population has been observed to vary with living conditions. If, and how, this affects sexual dimorphism in stature is not fully understood. We analyzed stature data from Swedish populations from the 10th to the end of the 20th century to investigate if male stature is more plastic than female stature in response to environmental changes. Further, we examined if there, as a consequence of this, exists an allometric relationship between male and female stature that is not caused by genetic factors, coupling greater stature with greater dimorphism. We found no significant change in stature from the 10th century to the 17th century, but a clear increase in both male and female stature during the 20th century, most likely because of improved living conditions. Regression analyses revealed no consistent change in sexual stature dimorphism over time for any of the time periods, including the 20th century. Further, we found no significant allometric relationship between male and female stature, and could consequently not identify any significant relationship between stature and stature dimorphism. Thus, contrary to previous suggestions, the regressions did not provide support for the assertion that male stature is more sensitive to environmental changes than female stature, nor that stature dimorphism increases with increasing stature.

Gustafsson A ，Werdelin L ，Tullberg BS ，Lindenfors P ... -  《AMERICAN JOURNAL OF HUMAN BIOLOGY》

Phylogenetic analyses of dimorphism in primates: evidence for stronger selection on canine size than on body size.

Phylogenetic comparative methods were used to analyze the consequences of sexual selection on canine size and canine size dimorphism in primates. Our analyses of previously published body mass and canine size data revealed that the degree of sexual selection is correlated with canine size dimorphism, as well as with canine size in both sexes, in haplorhine but not in strepsirrhine primates. Consistent with these results, male and female canine size was found to be highly correlated in all primates. Since canine dimorphism and canine size in both sexes in haplorhines were found to be not only related to mating system but also to body size and body size dimorphism (characters which are also subject to or the result of sexual selection), it was not apparent whether the degree of canine dimorphism is the result of sexual selection on canine size itself, or whether canine dimorphism is instead a consequence of selection on body size, or vice versa. To distinguish among these possibilities, we conducted matched-pairs analyses on canine size after correcting for the effects of body size. These tests revealed significant effects of sexual selection on relative canine size, indicating that canine size is more important in haplorhine male-male competition than body size. Further analyses showed, however, that it was not possible to detect any evolutionary lag between canine size and body size, or between canine size dimorphism and body size dimorphism. Additional support for the notion of special selection on canine size consisted of allometric relationships in haplorhines between canine size and canine size dimorphism in males, as well as between canine size dimorphism and body size dimorphism. In conclusion, these analyses revealed that the effects of sexual selection on canine size are stronger than those on body size, perhaps indicating that canines are more important than body size in haplorhine male-male competition.

Thorén S ，Lindenfors P ，Kappeler PM 《AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY》

Sexual dimorphism in stature and women's work: a phylogenetic cross-cultural analysis.

The following cultural variables were tested for their association with sexual dimorphism: sexual division of labor, type of subsistence (hunting and agriculture), and polygyny. The transmission of these traits among populations was investigated. All the traits were found to be associated with phylogeny, indicating that they are inherited from mother to daughter populations. A cross-cultural comparative method was used which controls for the statistical effects of similarity due to common ancestry (Galton's problem). Cross-cultural variation in sexual dimorphism in stature is negatively associated with women's contribution to subsistence. Women are taller, relative to men, in societies where women contribute more to food production. This may be because female nutritional status is better in these societies. No relationship was found between sexual dimorphism and other aspects of subsistence or polygyny. These results are discussed in relation to other studies of sexual dimorphism in modern and archaeological populations, and in relation to cross-cultural variation in sex-biased parental investment.

Holden C ，Mace R 《AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY》