Mate preferences and choices for facial and body hair in heterosexual women and homosexual men: influence of sex,population, homogamy,and imprinting-like effect

Recent research has reported that male body and facial hair influence women's mate preferences. However, it is not clear whether such preferences are typical for women or for individuals who prefer males as sexual partners. Here we explored body and facial hair in preferred and actual partners among men and women who prefer men as sexual partners. Including homosexual individuals provides a unique opportunity to investigate whether evolved mating psychologies are specific to the sex of the individual or sex of the partner. Based on an online survey of 1577 participants from Brazil and the Czech Republic, we found that, on average, homosexual men preferred hairier stimuli than heterosexual women, supporting past findings that homosexual men have strong preferences for masculine traits. Preferences for facial and body hair appear to be influenced less by sex of the preferred partner than sex of the individual, pointing to a possible sex-specific mating psychology. Further, Brazilians preferred bigger beards than Czechs, which was positively associated with the self-reported amount of beardedness in Brazil, suggesting that familiarity effects underpin cross-cultural differences in preferences for facial hair. Moreover, homosexual men preferred a self-similar degree of beardedness, and Czech women preferred a similar degree of beardedness as their fathers had during their childhood. However, these effects were not associated with the level of facial hair in their actual partners; in general, mate preferences and actual mate choices for facial and body hair differed. Thus, individual differences in some self-reported characteristics, cultural factors, and aspects of personal experience may modulate differences in preferences for masculine traits.     

Father's physique influences mate preferences but not the actual choice of male somatotype in heterosexual women and homosexual men

Body constitution plays an important role in human mate choice. Cross-cultural research reports that women on average prefer men with muscular physique. It is still unclear, however, what mechanisms influence the inter-individual variation in mate preferences and choices of partner's physique. In this study, we tested the mechanisms of an imprinting-like effect (similarity between father and an ideal and actual partner) and of homogamy (similarity between self and an ideal and actual partner) for male physique in heterosexual women and homosexual men. To assess the variation in male physique, we employed somatotype paradigm which characterizes body constitution using three components: endomorphic (heavy-set), mesomorphic (muscular), and ectomorphic (lean). In total, 149 homosexual men and 769 heterosexual women from the Czech Republic indicated the somatotype of their father, ideal and actual partner, and in homosexual men also their own somatotype. In line with previous research, the somatotype most preferred by both men and women was the mesomorphic, followed by the ectomorphic and the endomorphic one. Women's preferences for an ideal partner somatotype weakly correlated with their fathers' somatotype, especially in women who reported a positive relationship with their fathers during childhood. Among homosexual men, we found imprinting-like preferences only for the ectomorphic somatotype component and no significant association with the quality of their relationships with their fathers. We also found no significant relationship between the fathers' and actual partners' somatotype in either heterosexual women or homosexual men. Our research indicates that fathers have a rather weak influence on mate preference for somatotypes and no influence on actual mate choice.     

Mate preferences among Hadza hunter-gatherers

The literature on human mate preferences is vast but most data come from studies on college students in complex societies, who represent a thin slice of cultural variation in an evolutionarily novel environment. Here, I present data on the mate preferences of men and women in a society of hunter-gatherers, the Hadza of Tanzania. Hadza men value fertility in a mate more than women do, and women value intelligence more than men do. Women place great importance on men’s foraging, and both sexes rate character as important. Unlike college students, Hadza men place considerable importance on women being hard-working, and Hadza women cite looks about as often as men do. This research was made possible by a grant from the National Science Foundation and the Leakey Foundation. Frank Marlowe (B.A., M.A., M.F.A., Ph.D.) is associate professor in the Department of Anthropology, Harvard University. His research interests include the behavioral ecology of hunter-gatherers, mating systems, parental care, mate choice, and cooperation.     

Short stature in African pygmies is not explained by sexual selection

African pygmies' short stature has been studied for more than a century, but the evolution of this extreme phenotype remains unknown. The present study tests the hypothesis that sexual selection, through preference for short partners, may have contributed to the evolution of pygmies' stature. We gathered anthropometric and familial data from 72 Baka pygmy couples and 27 neighboring Nzimé nonpygmy couples from Cameroon. We found evidence for positive assortative mating and partial evidence for the male-taller norm in both groups. This is surprisingly close to results reported for many modern occidental populations, in which sexual selection is thought to exert a positive selective pressure on men height. Semistructured interviews of Baka pygmies concerning height and mate choice suggested that the male-taller norm matches mating preferences. Stature was also positively correlated with the number of serial marriages contracted by men of both populations, while the stature of women was not related to their mating success. Finally, we did not detect any linear or quadratic effect of height on reproductive success for either men or women. Altogether, our results demonstrate that stature influences mate choice in pygmies, and we argue that, if of any influence for sexual selection, mate choice should have favored tallness rather than shortness in our pygmy population. Consequently, this study establishes that sexual selection is a very unlikely candidate to account for the evolution of pygmies' short stature.     

Mate Choice Copying in Humans

There is substantial evidence that in human mate choice, females directly select males based on male display of both physical and behavioral traits. In non-humans, there is additionally a growing literature on indirect mate choice, such as choice through observing and subsequently copying the mating preferences of conspecifics (mate choice copying). Given that humans are a social species with a high degree of sharing information, long-term pair bonds, and high parental care, it is likely that human females could avoid substantial costs associated with directly searching for information about potential males by mate choice copying. The present study was a test of whether women perceived men to be more attractive when men were presented with a female date or consort than when they were presented alone, and whether the physical attractiveness of the female consort affected women’s copying decisions. The results suggested that women’s mate choice decision rule is to copy only if a man’s female consort is physically attractive. Further analyses implied that copying may be a conditional female mating tactic aimed at solving the problem of informational constraints on assessing male suitability for long-term sexual relationships, and that lack of mate choice experience, measured as reported lifetime number of sex partners, is also an important determinant of copying.     

Predator-induced maternal and paternal effects independently alter sexual selection

Parental experience alters survival-related phenotypes of offspring in both adaptive and nonadaptive ways, yielding rapid inter- and transgenerational fitness effects. Yet, fitness comprises survival and reproduction, and parental effects on mating decisions could alter the strength and direction of sexual selection, affecting long-term evolutionary trajectories. We used a full factorial design in which threespine stickleback (Gasterosteus aculeatus) mothers, fathers, both, or neither were exposed to a model predator at developmentally appropriate times to test for predator-induced maternal, paternal, and joint parental effects on daughters’ mating behavior. We tested the responsiveness, preferences, and mate choices of adult daughters in no-choice trials with wild-caught males who had varied sexual signals. Maternal and paternal predator exposure independently yielded daughters who preferred males who were intermediate in conspicuousness (with duller nuptial coloration and who courted less vigorously), relaxing the typical preference for the most conspicuous males. The combined effects of maternal and paternal predator exposure were not cumulative; when both parents were predator exposed, single-parent effects on mate preferences were reversed. Thus, we cannot assume that maternal and paternal effects additively combine to produce “parental” effects. Further, joint parental predator exposure yielded daughters who were three times less likely to mate at all. Stress-induced intergenerational parental effects on reproductive decisions such as those observed here may potentiate rapid transgenerational responses to novel and changing mating environments.     

Does Early Psychosocial Stress Affect Mate Choice?

Early psychosocial stress (e.g., parental divorce, abuse) is conjectured to place individuals on a developmental trajectory leading to earlier initiation of sexual activity, earlier reproduction, and having more sex partners than those with less early psychosocial stress. But does it also affect an individual’s mate choice? The present study examined whether early psychosocial stress affects preferences and dislikes for opposite-sex faces varying in masculinity/femininity, a putative indicator of mate quality, in premenopausal women (58 with a natural cycle, 53 pill-users) and 196 men. No significant three-way interactions were found when women selected the most or least preferred face with participant group (natural cycle, pill), conception risk (low, high), and early psychosocial stress (low, high) as between-subjects factors. Early psychosocial stress did not affect men’s face preferences when selecting the most preferred face. However, men with high early psychosocial stress disliked masculine faces significantly more so than men with low early psychosocial stress. Overall it was concluded that early psychosocial stress does not affect mate choice with the exception that men with high early psychosocial stress were more likely to dislike masculine female faces. It was suggested that men with high early psychosocial stress may dislike masculine female faces because they have nothing to gain from associating with women with such faces.     

Female Mate Preferences Among Pan troglodytes schweinfurthii of Kanyawara, Kibale National Park, Uganda

Studies of reproduction among chimpanzees traditionally have focused on the mating strategies of males. However, less is known about the mating strategies of female chimpanzees and whether they demonstrate mate choice. I investigated sexual behavior and female mate preference in the chimpanzees of the Kanyawara community. To estimate mate preferences, I analyzed female proceptivity and resistance rates of 6 estrous females toward a total of 13 males as well as male solicitation and aggression rates toward females. Males solicited some females more often than others for mating and preferred them throughout estrus, not only during the periovulatory period (POP), when conception was most likely. In contrast, though females had strong mate preferences in both non-POP and POP, their mate preferences were not consistent between the 2 phases. The shift in mate preferences is evidence of a promiscuous yet tactical mating strategy to confuse paternity. Further, females were more proceptive and generally less resistant toward eschewed males in non-POP and more proceptive and less resistant toward preferred males in POP. Hence, the results indicate that females attempted to mate selectively during the fertile phase. Kanyawara female chimpanzees appear to change their mating strategies and selectivity during estrus and thus may pursue a mixed reproductive strategy. The tactic may allow females to deceive males, indicating that promiscuity among chimpanzee females may be more strategic than previously thought.     

The evolution of parent–offspring conflict over mate choice

In human societies, parents often have a strong influence on the mate choice of their offspring. Moreover, empirical studies show that conflict over mate choice between parents and offspring is widespread across human cultures. Here we provide the first theoretical investigation into this conflict, showing that it may result from an underlying evolutionary conflict over parental resource distribution. We present a series of evolutionary simulations in which we gradually expand a standard model of sexual selection by the stepwise addition of elements of parental involvement. In our model, females obtain resources enhancing their fecundity from both their chosen mate and their parents. Potential mates differ in their ability to provide resources and may signal this ability. Both females and their parents can develop a preference for the signal, with both preferences influencing the realized mate choice of the female. Parents may differentially allocate resources among their daughters depending on the resource-provisioning abilities of their sons-in-law. When fecundity returns on investment are diminishing, we find that parents invest most in daughters whose mates provide few resources. Subsequently, the daughters evolve to exploit this allocation rule through their mate choice, which is not in the parents' best interests. This results in a conflict over mate choice between parents and their offspring, manifested as an on-going divergence of offspring and parental preferences. We predict that the conflict should be most pronounced when fathers, as opposed to mothers, control resource allocation.     

Ethnic differences in anthropometric characteristics of young children and their parents

The distribution of body fat, or fat patterning, is an important risk factor for cardiovascular disease and diabetes, independent of obesity. Furthermore, the incidence of cardiovascular disease and diabetes varies by ethnicity. We documented ethnic differences in anthropometric characteristics and body fat distribution between Anglo, Black, and Mexican American men (n = 101), women (n = 245), boys (n = 111), and girls (n = 111). We used aggregates of skinfold measures to examine ethnic differences in the deposition of fat in body compartments (body, trunk, leg, and arm) and analyzed trunk-extremity skinfold ratios to determine which best reflected ethnic differences in fat distribution. The results show that Mexican American mothers have larger skinfold ratios and more body fat (as determined by skinfold aggregates) than either Anglo or Black American mothers, whereas Black American mothers have larger ratios than Anglo American mothers. Mexican American fathers also have larger skinfold ratios but not more body fat (skinfold aggregates) than Anglo American fathers. Mexican American fathers have more body fat than Black American fathers, but we found no differences between skinfold ratios. The ethnic differences among children in skinfold ratios and aggregates are similar to those found among fathers, with more differences among girls than boys. Fat patterning differences do exist among the three ethnicities, with greater trunk fat among Mexican and Black Americans. Those ethnicities are known to be at higher risk for cardiovascular disease and diabetes.     

Sexual selection under parental choice: a revision to the model

Across human cultures, parents exercise considerable influence over their children’s mate choices. The model of parental choice provides a good account of these patterns, but its prediction that male parents exercise more control than female ones is not well founded in evolutionary theory. To address this shortcoming, the present article proposes a revision to the model. In particular, parental uncertainty, residual reproductive value, reproductive variance, asymmetry in the control of resources, physical strength, and access to weaponry make control over mating more profitable for male parents than female ones; in turn, this produces an asymmetrical incentive for controlling mate choice. Several implications of this formulation are also explored.     

Men’s reproductive investment decisions

Using questionnaire data completed by 170 men, we examine variation in paternal investment in relation to the trade-off between mating and parenting. We found that as men’s self-perceived mate value increases, so does their mating effort, and in turn, as mating effort increases, paternal investment decreases. This study also simultaneously examined the influence on parental investment of men’s mating effort, men’s perception of their mates’ fidelity, and their perceived resemblance to their offspring. All predicted investment. The predictors of investment are also tested independently for men who are still in a relationship with the mother of their children and those that are separated from her. Finally we examine how self-perceived mate value affects how men respond to variation in paternity confidence. Men with a self-perceived low mate value were less likely to respond to lowered mate fidelity by reducing their parental investment compared with men with a self-perceived high mate value.     

Adult sex ratio variation: implications for breeding system evolution

Adult sex ratio (ASR) exhibits immense variation in nature, although neither the causes nor the implications of this variation are fully understood. According to theory, the ASR is expected to influence sex roles and breeding systems, as the rarer sex in the population has more potential partners to mate with than the more common sex. Changes in mate choice, mating systems and parental care suggest that the ASR does influence breeding behaviour, although there is a need for more tests, especially experimental ones. In the context of breeding system evolution, the focus is currently on operational sex ratios (OSRs). We argue that the ASR plays a role of similar importance and urge researchers to study the ASR and the OSR side by side. Finally, we plead for a dynamic view of breeding system evolution with feedbacks between mating, parenting, OSR and ASR on both ecological and evolutionary time scales.     

Parental effects: physiological age, mating pattern, and diapause duration on diapause incidence of progeny in the cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae)

The cabbage beetle, Colaphellus bowringi Baly, is a short-day species that has both a facultative summer and winter adult diapause. In this study, we systematically investigated the effects of parental physiological age, mating pattern (including mating frequency and delayed mating), and diapause duration on the diapause incidence of progeny in the beetle. As parents aged, progeny diapause incidences showed considerable inter-parental variability and an abnormally varying pattern, but their predicting line was approximate to horizontal when reared under constant conditions. There was significant difference in progeny diapause incidence between multiple-mating and once-mating treatments. Higher diapause incidences in the progeny were observed in delayed-mating treatments. Progeny diapause incidences increased as diapause duration in the parental generation increased, and hibernating individuals produced more diapausing progeny than aestivating ones. Reciprocal cross tests between the post-diapause adults and non-diapause adults with no diapause history showed that the effect of parental diapause duration on the progeny diapause incidence was determined by both mothers and fathers but the mothers appeared to have a stronger effect than the fathers. Our results suggest that the parental age effect in Colaphellus bowringi might not be simply age-dependent, but may be controlled by the interaction of multiple factors, including physiological, environmental, behavioral and genetic factors. We discuss the ecological and physiological significance of these findings.     

斜纹夜蛾的性选择行为

【目的】为了解斜纹夜蛾Spodoptera litura Fabricius体重、日龄、交配经历及形态特征对其性选择行为的影响。【方法】本实验通过标记成虫后,采用观察记录的方法对其进行探究。【结果】斜纹夜蛾雌虫的体重对雄虫的性选择影响比较明显,体重较大雄虫优先选择体重较小的雌虫(71.43%),而体重较小雄虫喜欢选择体重较大的雌虫(72.00%)。体重较大和体重较小的雄虫都能获得体重较大雌虫的交配选择,但是体重较大者被选择的机会更大(70.00%),体重较小的雄虫不能获得体重较小雌虫的选择。雄虫仅选择1日龄的雌虫,而雌虫偏向选择3日龄和5日龄雄虫。交配经历影响斜纹夜蛾的性选择,未交配的雄虫优先选择未交配的雌虫(86.67%),但未交配的雌虫则优先选择已交配的雄虫(66.67%)。雄虫的形态特征(体长、翅展、腹长、复眼间距和触角长)对雌虫性选择有较明显的影响,但雌虫的形态特征除翅展的大小外,其体长、腹长、复眼间距和触角长等形态特征在雄虫选择进行交配中的作用不大。【结论】体重、日龄、交配经历及形态特征都能不同程度影响斜纹夜蛾的性选择行为。     

MHC-associated mating strategies and the importance of overall genetic diversity in an obligate pair-living primate

Mate choice is one of the most important evolutionary mechanisms. Females can improve their fitness by selectively mating with certain males. We studied possible genetic benefits in the obligate pair-living fat-tailed dwarf lemur (Cheirogaleus medius) which maintains life-long pair bonds but has an extremely high rate of extra-pair paternity. Possible mechanisms of female mate choice were investigated by analyzing overall genetic variability (neutral microsatellite marker) as well as a marker of adaptive significance (major histocompatibility complex, MHC-DRB exon 2). As in human medical studies, MHC-alleles were grouped to MHC-supertypes based on similarities in their functional important antigen binding sites. The study indicated that females preferred males both as social and as genetic fathers for their offspring having a higher number of MHC-alleles and MHC-supertypes, a lower overlap with female’s MHC-supertypes as well as a higher genome wide heterozygosity than randomly assigned males. Mutual relatedness had no influence on mate choice. Females engaged in extra-pair mating shared a significant higher number of MHC-supertypes with their social partner than faithful females. As no genetic differences between extra-pair young (EPY) and intra-pair young (IPY) were found, females might engage in extra-pair mating to ‘correct’ for genetic incompatibility. Thus, we found evidence that mate choice is predicted in the first place by the ‘good-genes-as-heterozygosity hypothesis’ whereas the occurrence of extra-pair matings supports the ‘dissassortative mating hypothesis’. To the best of our knowledge this study represents the first investigation of the potential roles of MHC-genes and overall genetic diversity in mate choice and extra-pair partner selection in a natural, free-living population of non-human primates.     

Neighbouring‐group composition and within‐group relatedness drive extra‐group paternity rate in the European badger (Meles meles)

Extra‐group paternity (EGP) occurs commonly among group‐living mammals and plays an important role in mating systems and the dynamics of sexual selection; however, socio‐ecological and genetic correlates of EGP have been underexplored. We use 23 years of demographic and genetic data from a high‐density European badger (Meles meles) population, to investigate the relationship between the rate of EGP in litters and mate availability, mate incompatibility and mate quality (heterozygosity). Relatedness between within‐group assigned mothers and candidate fathers had a negative quadratic effect on EGP, whereas the number of neighbouring‐group candidate fathers had a linear positive effect. We detected no effect of mean or maximum heterozygosity of within‐group candidate fathers on EGP. Consequently, EGP was associated primarily with mate availability, subject to within‐group genetic effects, potentially to mitigate mate incompatibility and inbreeding. In badgers, cryptic female choice, facilitated by superfecundation, superfoetation and delayed implantation, prevents males from monopolizing within‐group females. This resonates with a meta‐analysis in group‐living mammals, which proposed that higher rates of EGP occur when within‐group males cannot monopolize within‐group females. In contrast to the positive meta‐analytic association, however, we found that EGP associated negatively with the number of within‐group assigned mothers and the number of within‐group candidate fathers; potentially a strategy to counter within‐group males committing infanticide. The relationship between the rate of EGP and socio‐ecological or genetic factors can therefore be intricate, and the potential for cryptic female choice must be accounted for in comparative studies.     

Variation in human mate choice: simultaneously investigating heritability, parental influence, sexual imprinting, and assortative mating

Human mate choice is central to individuals' lives and to the evolution of the species, but the basis of variation in mate choice is not well understood. Here we looked at a large community-based sample of twins and their partners and parents ([Formula: see text] individuals) to test for genetic and family environmental influences on mate choice, while controlling for and not controlling for the effects of assortative mating. Key traits were analyzed, including height, body mass index, age, education, income, personality, social attitudes, and religiosity. This revealed near-zero genetic influences on male and female mate choice over all traits and no significant genetic influences on mate choice for any specific trait. A significant family environmental influence was found for the age and income of females' mate choices, possibly reflecting parental influence over mating decisions. We also tested for evidence of sexual imprinting, where individuals acquire mate-choice criteria during development by using their opposite-sex parent as the template of a desirable mate; there was no such effect for any trait. The main discernible pattern of mate choice was assortative mating; we found that partner similarity was due to initial choice rather than convergence and also at least in part to phenotypic matching.     

Same-Sex Gaze Attraction Influences Mate-Choice Copying in Humans

Mate-choice copying occurs when animals rely on the mating choices of others to inform their own mating decisions. The proximate mechanisms underlying mate-choice copying remain unknown. To address this question, we tracked the gaze of men and women as they viewed a series of photographs in which a potential mate was pictured beside an opposite-sex partner; the participants then indicated their willingness to engage in a long-term relationship with each potential mate. We found that both men and women expressed more interest in engaging in a relationship with a potential mate if that mate was paired with an attractive partner. Men and women''s attention to partners varied with partner attractiveness and this gaze attraction influenced their subsequent mate choices. These results highlight the prevalence of non-independent mate choice in humans and implicate social attention and reward circuitry in these decisions.     

Are men and women really so different?

Distinct differences in the behaviour and preferences of men and women have conventionally been attributed to Trivers' powerful insights regarding the impact of parental investment on sexual selection and mating systems. This has spawned a huge literature about the evolutionary significance of human sex differences. But are men and women really so different? An elegant new study shows that men and women are strikingly similar in their mate preferences. Have conventional models blinded us to the obvious, and precluded the posing of far more interesting questions?