Female Infidelity Research Articles

The Evolution of Infidelity in Socially Monogamous Passerines: Neglected Components of Direct and Indirect Selection

A recent study by Göran Arnqvist and Mark Kirkpatrick in the American Naturalist (165:S26–S37) suggested that female polyandry in birds is not driven by females because quantitative genetic approximations of selection demonstrated that indirect selection for female infidelity is weaker than natural selection against it. Instead, it was argued that extrapair copulations are the result of antagonistic selection on male behavior driving female coercion. While the approach and framework of the study were very good, the conclusions of the study were premature because a number of potential adaptive components of polyandry were unaccounted for, and several critical assumptions are unsupported by the current empirical data. Our understanding of extrapair paternity in birds, and perhaps polyandry in general, will be improved by a better empirical understanding of the direct benefits of fertility assurance and postcopulatory cryptic female choice and the relationship between polyandry and male investment. In addition, we need to develop a greater awareness of the limitations of trying to study behavior by proxy in the molecular laboratory. Together, these challenges and the framework recently presented should improve our understanding of the true function of extrapair paternity in birds.

Daring wives: insight into women's desires for extramarital affairs

Introduction Out of the Closet: The Fair Sex and Infidelity Drastic Double Standards and Daring Wives What a Difference a Century Makes: Female Infidelity and the Double Standard Not So Sweet Home: Stay in the Abode Wives Wanderlust while They Work: Working Wives and Outside Romance Young and Restless: The World's Their Oyster Older and Bolder: Under Cover with a Younger Lover Remarriages and Regrets: Out of Step with Stepfamilies Same Sex Affairs: Wives with Women Lovers Sex Goes Awry Conclusion: Implications for Marriage and American Society

Amour in the Shubbery: Reading the Detail of English Adultery Trial Publications of the 1780s

This article examines how late-eighteenth-century knowledge about adultery was constituted through English publications based on legal evidence of female infidelity. A mass of published fragments and hints produced distinctive perspectives on contemporary cultural and social issues. Two cases of 1785, which involved shrubberies, exemplify how such discussion appropriated and re-contextualized discourses, including that of landscape improvement. Shrubbery brought additional resonances to an adultery trial literature which in the 1780s played with ideas about the freedom and rights of women within marriage. However, shrubbery's adulterous politics of subordination and objectification also had implications for the politics and aesthetics of landscape itself.

Comparative evolutionary psychology of sperm competition.

A comparative evolutionary psychological perspective predicts that species that recurrently faced similar adaptive problems may have evolved similar psychological mechanisms to solve these problems. Sperm competition provides an arena in which to assess the heuristic value of such a comparative evolutionary perspective. The sperm competition that results from female infidelity and polyandry presents a similar class of adaptive problems for individuals across many species. The authors first describe mechanisms of sperm competition in insects and in birds. They suggest that the adaptive problems and evolved solutions in these species provide insight into human anatomy, physiology, psychology, and behavior. The authors then review recent theoretical and empirical arguments for the existence of sperm competition in humans and discuss proposed adaptations in humans that have analogs in insects or birds. The authors conclude by highlighting the heuristic value of a comparative evolutionary psychological approach in this field.

Effects of partner conception risk phase on male perception of dominance in faces

Several studies have suggested that women may prefer to engage in extra-pair copulations with males who appear dominant and to do so near ovulation. While there is some evidence that males are more jealous of dominant rivals and more proprietary when their partners are near ovulation, there is none that suggests the existence of counterstrategic perceptual shifts that mirror those seen in women. We provide such evidence here. Composites of male faces that were either high or low in rated dominance were presented to male participants who provided ratings of dominance. A three-way interaction between stimulus-face dominance, partner conception risk phase, and partner oral contraceptive use was found; men whose partners did not use an oral contraceptive and were in the high conception risk phase of their cycle displayed increased dominance ratings of high-dominance male faces. We conclude that males have evolved counterstrategies to deal with female infidelity that include an overattribution of dominance to those rivals most likely to present a threat at times when that threat is greatest. This overattribution is likely to lead to increases in jealousy and mate-retention behaviors.

The Strength of Direct Selection against Female Promiscuity Is Associated with Rates of Extrapair Fertilizations in Socially Monogamous Songbirds

A costs-benefits approach has frequently been used to understand the evolutionary origin and maintenance of promiscuity in animal populations. Recent meta-analyses suggest that direct costs to unfaithful females outweigh indirect benefits from infidelity in socially monogamous songbirds, suggesting that in this taxa, extrapair fertilization (EPF) evolved primarily as a self-interest male tactic. Here we present results of comparative analysis to show that standardized selection gradients acting against female infidelity (direct costs of promiscuity) explain variation in EPF rates at an interspecific level in passerines. This result confirms that costs to females resulting from reduced parental care from cheated males constrain promiscuity in this group. Our data indicate that females exert resistance over EPFs when the costs of infidelity are high and, conversely, that the rate of EPFs increases when selection on females to defend themselves against EPF attempts by males is weak and costs of infidelity are low.

Genetic Influence on Reproductive Behavior in Female Rhesus Macaques

AbstractCommentary on Cherkas et al. (2004). Genetic Influences on Female Infidelity and Number of Sexual Partners in Humans: A Linkage and Association Study on the Role of the Vasopressin Receptor Gene (AVPR1A). Twin Research, 7, 649–658.

Wet and dry sex—the impact of cultural influence in modifying vaginal function

In a number of countries, but especially in sub-Saharan Africa, many women practice so-called “dry sex” usually by instilling vaginally various astringent substances to dry up the normal lubrication fluid created by sexual arousal and give the impression the vagina is still virginal tight and “hot”. This behaviour is normally undertaken to conform to male-dominated cultural concepts that vaginal lubrication fluid (“wet sex”) putatively indicates female infidelity, possible infection, licentiousness, coldness and makes coitus less pleasurable because of reduced friction. Many of the chemical substances employed for this can produce damage to the cervical and vaginal epithelium and thus possibly facilitate infection and transmission of HIV although no causal relation between possible damage and disease transmission has yet been definitively established. Few studies, however, have been conducted to examine the actions of the substances on vagina/cervical structures and their many functions.

The Evolution of Infidelity in Socially Monogamous Passerines: The Strength of Direct and Indirect Selection on Extrapair Copulation Behavior in Females

Many studies have been aimed at understanding the maintenance of female infidelity in socially monogamous birds. Because engaging in extrapair copulations (EPCs) is believed to be costly for females, it has been argued that EPC behavior must bring indirect benefits to females by elevating offspring fitness. We use empirical data from the literature to assess the relative strength of indirect and direct selection on female EPC behavior, using quantitative genetic approximations of selection. This analysis confirmed that there is generally negative direct selection on EPC behavior caused by depressed paternal investment by social males. In contrast, there was no significant positive indirect selection on EPC behavior in females. A comparison between the two types of selection suggests that the force of direct negative selection is generally much stronger than that of indirect positive selection. Indirect selection is thus unlikely to maintain EPC behavior in the face of direct selection against it. We suggest that EPCs may instead be the result of antagonistic selection on loci influencing the outcome of male-female encounters and that EPC behavior per se may not be adaptive for females but may reflect sexual conflict due to strong selection in males to achieve extrapair copulations.

Genetic Influences on Female Infidelity and Number of Sexual Partners in Humans: A Linkage and Association Study of the Role of the Vasopressin Receptor Gene (AVPR1A)

AbstractIn humans, in contrast to animals, the genetic influences on infidelity are unclear. We report here a large study of over 1600 unselected United Kingdom female twin pairs who confidentially reported previous episodes of infidelity and total lifetime number of sexual partners, as well as attitudes towards infidelity. Our findings demonstrate that infidelity and number of sexual partners are both under moderate genetic influence (41% and 38% heritable, respectively) and the genetic correlation between these two traits is strong (47%). Conversely, attitudes towards infidelity are driven by shared and unique environmental, but not genetic, influences. A genome-wide linkage scan identified three suggestive but nonsignificant linkage areas associated with infidelity and number of sexual partners on chromosomes 3, 7 and 20 with a maximum LOD score of 2.46. We were unsuccessful in associating infidelity or number of sexual partners with a locus implicated in other mammals' sexual behavior, the vasopressin receptor gene. Nonetheless, our findings on the heritabil-ity of sexual infidelity and number of sexual partners provide support for certain evolutionary theories of human sexual behavior, as well as justifying further genetic and molecular research in this domain.

Mate retention, semen displacement, and human sperm competition: a preliminary investigation of tactics to prevent and correct female infidelity

Sperm competition is the competition between the sperm of two or more males to fertilize a female’s egg(s). We examined how men under a high recurrent risk of sperm competition might attempt to prevent and correct their partners’ sexual infidelity. Three hundred and five males drawn from universities and surrounding communities rated their partner’s physical attractiveness and personality characteristics (to assess their recurrent risk of sperm competition), and reported their use of tactics designed to prevent partner infidelity (mate retention tactics) and their use of specific copulatory behaviors arguably designed to displace the semen of rival men (semen-displacing behaviors). As hypothesized, men at a high recurrent risk of sperm competition were more likely to use mate retention tactics and to perform semen-displacing behaviors.

Murder and the reasonable man: passion and fear in the criminal courtroom

Part 2 of 2. Part 1 is located: http://ssrn.com/abstract=394601 This book examines the influence of masculinity, heterosexuality, and race norms on the reasonableness requirement in two criminal law defenses: the doctrine of provocation and the defense of self-defense. I argue that certain defendants are better able than others to bolster their claims of reasonableness by relying on dominant social norms and illustrate this point by examining three types of cases: (1) female infidelity killings, (2) gay panic killings, and (3) racialized self-defense cases (both private claims of self-defense and police use of deadly force against persons of color). Even though these three types of cases may seem completely unconnected at first glance, they are linked by the defendant's reliance on social norms to bolster his (or her) claim of reasonableness.I offer three proposals for reform. My first proposal is theoretical - rather than relying on a positivist conception of reasonableness (or one that focuses on what the average or typical person would have believed or done), I suggest we ought to also utilize a normative conception of reasonableness (or one that focuses on what actions ought to be considered reasonable). To implement this normative conception of reasonableness, I offer a practical reform: a race-switching (or gender-switching or sexual orientation-switching) jury instruction. Upon a motion by the prosecutor or defense attorney or if the judge sua sponte thinks it appropriate, the judge would instruct jurors that they may switch the races (or genders or sexual orientation) of the defendant and victim and determine whether they would come to a different result after switching. If so, then jurors may wish to reconsider the case with the knowledge that they may have been relying upon racial stereotypes (or masculinity or heterosexuality norms) the first time around. Finally, I offer a doctrinal reform that raises the bar for all defendants claiming provocation or self-defense which is really just a clarification of existing law in the case of self-defense. In contrast to the current focus on reasonableness of beliefs and emotions, this reform (which I call the Act-Belief Distinction) would require the jury to find that both the defendant's beliefs (or emotions) and his or her acts were reasonable.

Sex-specific associative learning cues and inclusive fitness benefits in the Seychelles warbler.

In cooperative breeding vertebrates, indirect fitness benefits would be maximized by subordinates that accurately assess their relatedness to group offspring and preferentially help more closely related kin. In the Seychelles warbler (Acrocephalus sechellensis), we found a positive relationship between subordinate-nestling kinship (determined using microsatellite marker genotypes) and provisioning rates, but only for female subordinates. Female subordinates that helped were significantly more related to the nestlings than were nonhelpers, and the decision to help appears to be based on associative learning cues. High levels of female infidelity means that subordinates cannot trust their legitimacy through the male line, consequently they appear to use the continued presence of the primary female, but not the primary male, as a reliable cue to determine when to feed nestlings. By using effective discrimination, female subordinates are able to maximize the indirect benefits gained within a cooperative breeding system otherwise driven primarily by direct breeding benefits.

The human penis as a semen displacement device

Inanimate models were used to assess the possibility that certain features of the human penis evolved to displace semen left by other males in the female reproductive tract. Displacement of artificial semen in simulated vaginas varied as a function of glans/coronal ridge morphology, semen viscosity, and depth of thrusting. Results obtained by modifying an artificial penis suggest that the coronal ridge is an important morphological feature mediating semen displacement. Consistent with the view of the human penis as a semen displacement device, two surveys of college students showed that sexual intercourse often involved deeper and more vigorous penile thrusting following periods of separation or in response to allegations of female infidelity.

Is social dominance a sex-specific strategy for infidelity?

The current study investigated personality, psychopathy and mating effort of 84 adults recruited from a large office setting who admitted infidelity whilst involved in another relationship. These were compared with individuals who had not been unfaithful. Measurement scales were reduced by principal components analysis to three general factors; social dominance, manipulativeness, and openness. There was no sex difference in social dominance or openness. Males were higher on the manipulativeness factor. There were no differences in the social dominance or openness factors for individuals admitting affairs compared to those who had not; males who admitted affairs were higher in social dominance. There was an interaction between sex and having had an affair (or not) for the social dominance, this indicated males who had committed infidelity were higher on the social dominance dimension than females who were also unfaithful, the reverse was the case for males and females who had not had affairs. Manipulativeness predicted the number of affairs had and their emphasis on sexuality, whereas social dominance did not. These results suggest male and female infidelity is underpinned by differential personality types as well as differential sexual strategies.

Male honor and female fidelity: implicit cultural scripts that perpetuate domestic violence.

Two studies explored how domestic violence may be implicitly or explicitly sanctioned and reinforced in cultures where honor is a salient organizing theme. Three general predictions were supported: (a) female infidelity damages a man's reputation, particularly in honor cultures; (b) this reputation can be partially restored through the use of violence; and (c) women in honor cultures are expected to remain loyal in the face of jealousy-related violence. Study 1 involved participants from Brazil (an honor culture) and the United States responding to written vignettes involving infidelity and violence in response to infidelity. Study 2 involved southern Anglo, Latino, and northern Anglo participants witnessing a "live" incident of aggression against a woman (actually a confederate) and subsequently interacting with her.

Avian behaviour: Altruism and infidelity among warblers.

In cooperatively breeding vertebrates, indirect fitness benefits1,2 are maximized by subordinates who choose to help their own closely related kin after accurately assessing their relatedness to the group's offspring3,4,5. Here we show that in the cooperatively breeding Seychelles warbler (Acrocephalus sechellensis), female subordinates help to raise new nestlings by providing them with food only when the offspring are being raised by parents who also fed the subordinates themselves when they were young3. These helper females use the continued presence of the primary female, rather than of the primary male, as their provisioning cue — presumably because female infidelity is rife in this species6, making their relatedness to the father less reliable.

Extra-pair paternity and mate-guarding behaviour in the brown thornbill

We used multilocus DNA fingerprinting to assess parentage in the brown thornbill, Acanthiza pusilla, a socially monogamous Australian passerine. Extra-pair paternity was uncommon (6.2% of 178 offspring; 11.9% of 67 broods) and there was no evidence of intra-specific brood parasitism. Extra-pair paternity was limited because pairs spent more time together when females were fertile and males were able to evict intruding males before they could approach the female. Males were responsible for the close proximity of partners during the fertile period. Mate guarding therefore appears to be a male tactic aimed at preventing female infidelity rather than a cooperative behaviour of the pair aimed at preventing extra-pair copulations and/or female harassment. Females did not attempt to escape male guarding and were rarely observed to solicit copulations from intruding males. Nevertheless, females paired to smaller and younger males were more likely to cuckold their mates than females paired to larger and older males. This suggests that females may be more likely to seek or accept extra-pair matings when paired to small, young males or that old, large males are better at preventing their mates from engaging in extra-pair copulations. We found that male age but not male size influences mate-guarding behaviour. Older males tended to respond more aggressively to intruders. We therefore speculate that the relationship between male size/age and extra-pair paternity in brown thornbills may arise because female thornbills prefer large males as mates but are unable to express this preference as easily when paired to older males.

Infidelity as a transaction between social mates

Why are some females faithful to their mates, whereas others are promiscuous, and why do males tolerate cuckoldry, raising both their own and the young of another male? Determining these answers is central to our understanding of mating systems and sexual selection. The past decade has been marked by an infusion of molecular analyses of paternity, revealing enormous variation in cuckoldry rates across species, populations and even individuals. Arguments have been waged about the underlying determinants of the levels of cuckoldry and female infidelity. In many species, females might be largely in control of which male or males they mate with. Understanding promiscuous behaviour might, therefore, be achieved best by examining the costs and benefits of cuckoldry to females. Until now, however, no formal framework existed that simultaneously took into account both female and male interests to provide a comprehensive explanation of how these costs and benefits might interact to shape the evolution of infidelity.Janet Shellman-Reeve and H. Kern Reeve 1xExtra-pair paternity as the result of reproductive transactions between paired mates. Shellman-Reeve, J.S and Reeve, H.K. Proc. R. Soc. London B Biol. Sci. 2000; 267: 2543–2546Crossref | Scopus (16)See all References1 have now developed a mathematical model similar to transactional (optimal skew or concession) models in which cuckoldry in broods receiving biparental care is viewed as emerging from a transaction between the mated pair. The model assumes that a female can obtain good genes (i.e. better genes than from her current mate) by mating with a second male. The model also assumes that males can assess their potential risk of being cuckolded, but might not be able to recognize their own young within the brood. If they suspect, however, that their paternity is sufficiently low, they might choose to abandon both their mate and the brood. Conversely, a female can choose to divorce her mate and raise a brood comprised entirely of cuckolded young on her own. This elegant model provides the first formal framework for evaluating how good genes can tradeoff with good care in determining the frequency of cuckoldry. The model shows that a female is expected to become more promiscuous when the value of the care of her mate (in terms of offspring survivorship) becomes lower or when the genetic quality of a potential cuckolder male becomes higher relative to that of the current mate of the female. Given such circumstances, a paired male can only demand the small amount of paternity that a female is willing to give him before she discounts his value altogether and chooses to raise cuckolded young on her own.Cuckoldry and parental care is perhaps best studied in birds, and the transactional model of Shellman-Reeve and Reeve provides a remarkably unified explanation for all of the major empirically observed predictors of cuckoldry rates in birds that provide biparental care. Perhaps most importantly, the model makes an important connection between the extensive theory of transactions and theory of mate choice and parental investment. It is probable that, given the depth of transactional theory, many more insights will arise from this new association. For example, ‘tug-of-war’ models might be amendable to address cuckoldry and parental care in mating systems in which males have more control of paternity, such as might be the case in external fertilizers, or systems where males are larger than females. Nevertheless, it appears that transactional theory might provide the basis for a truly unifying theory of social interactions.

The logic of Ménage à Trois.

Recent studies of socially monogamous species have shown that in many cases females do not copulate exclusively with their pair mates, but are also receptive to other males. The explanation usually given for unfaithful female behavior is that most females are unable to bond with a male they would prefer as genetic father to their offspring. To secure male assistance the female therefore pairs with an available male but also copulates with males of supposedly higher genetic quality. Here we offer an alternative evolutionary explanation for female infidelity, which does not rely upon this 'Good Genes hypothesis of female choice. We show with a simple model that in an evolutionary game between three players, a male, a female and a male lover, solutions exist in which the female can secure more assistance from her mate by being receptive to other males. We conclude that female sexuality can have a decisive role in regulating social behaviour, in which the fertile female is the driving force.