Confidence of paternity,divorce, and investment in children by Albuquerque men

Using a sample of men living in Albuquerque, NM, we examined the relationship between paternity confidence and men's investment in children. In humans, men may reduce their investment in a child in two ways: indirectly, by ending their relationship with the child's mother and ceasing to cohabit with the child (e.g., divorce), and directly, by allocating less time and fewer resources to the child. In this article, we tested two hypotheses regarding the effect of paternity confidence on investment in children: (1) men will be more likely to divorce women if they suspect or are sure that they are not the father of their wife's child, and (2) controlling for divorce, men will reduce direct investments in low paternity confidence children relative to high paternity confidence children. The first hypothesis was supported by the data. The second hypothesis was supported for two out of three measures of paternal investment we examined; low paternity confidence reduces the time men spend with a child in a group with other children or adults, and it reduces extensive involvement with the child's educational progress; there was no effect of paternity confidence on the amount of time men spend with children in one-on-one interactions. We also examined the effects of unstated paternity confidence (e.g., when men decline to answer the question) on divorce and paternal investment. Overall, the results suggested that paternity confidence plays an important role in shaping men's relationships with women and with their putative genetic children.     

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.     

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.     

Cues to paternity: Do partner fidelity and offspring resemblance predict daughter-directed sexual aversions?

Despite the profound influence of relatedness on mating and cooperative behavior in humans, the cues men use to assess paternity and guide offspring-directed behavior have yet to be fully resolved. According to leading theories of kin detection, kinship cues should influence both sexual and altruistic motivations because of fitness consequences associated with inbreeding and welfare tradeoff decisions, respectively. Prior work with paternity assessment, however, has generally evaluated candidate cues solely by demonstrating associations with altruism. Here we (i) replicate past work that found effects of phenotypic resemblance and perceived partner fidelity on offspring investment; and (ii) evaluate whether both phenotypic resemblance and perceived partner fidelity meet the more stringent criteria suggested by theory—that is, whether they also predict inbreeding aversions. We report on two studies, one from a population-based sample of Finnish fathers (N?=?390), the other from a Mechanical Turk sample (N?=?700), and furnish evidence in strong support of perceived partner fidelity as a cue to paternity. Support for resemblance as a cue to paternity was decidedly weaker. We discuss a non-kin-based role that resemblance might play in altruistic decision-making, consider whether men might use additional kinship cues to meet the computational challenges associated with paternity assessment, and provide suggestions for future research.     

Partner preferences in the context of concurrency: What Himba want in formal and informal partners

Research on human mate preferences that distinguishes between short- and long-term partners has been conducted mainly in industrialized societies, where multiple mating and concurrent partnerships are stigmatized. However, cross-culturally, there is significant variation in the frequency and the level of acceptance of such relationships. Furthermore, the dichotomy between short- and long-term partnerships does not fully describe the diversity in actual extra-pair behavior, which ranges from single sexual encounters to multi-year love affairs. Here we present another comparison, between formal (marital) and informal (non-marital) partners, which we feel better captures this diversity. We assess the traits that men and women prefer in each type of partner among Himba pastoralists, where concurrent partnerships are common and accepted for both sexes. We situate our findings in relation to three main explanations for concurrent partnerships: dual-mating, trading-up and multiple investors. We find some similarities with the existing literature in the traits that are listed as important, including physical attractiveness, wealth and intelligence. Our evidence suggest that Himba men follow a dual strategy, preferring hard-working wives and attractive girlfriends. Women's preferences align most strongly with a multiple investors explanation, most clearly articulated through their preferences for wealthy husbands and generous boyfriends. Limited support is also found for a dual-mating strategy in women. These findings suggest that local cultural norms and ecologies modulate mate preferences in important ways.     

Intersexual conflict across women's ovulatory cycle

A growing literature shows that the features women find particularly attractive in men vary across the ovulatory cycle. Women furthermore appear to more frequently report attraction to men other than primary partners when they are fertile in their cycle than in the infertile luteal phase. Previous studies have shown that men are more vigilant of or attentive to their primary partners during the fertile phase compared to the luteal phase. This study had several aims: First, to replicate and extend previous findings concerning men's vigilance of partners using male as well as female reports of men's behavior; second, to examine changes in women's behavior toward partners across the cycle; third, to examine ways in which women resist men's attempts to mate-guard across the cycle. Results indicate that (a) men are particularly self-assertive toward partners when their partners are fertile; (b) similarly, women are especially self-assertive toward partners when they are fertile; (c) women report engaging in more behaviors that resist male vigilance and mate guarding when they are fertile, especially in ways that are unobservable to male partners; and (d) these effects are especially strong when women themselves report greater attraction to men other than partners when they are fertile, compared to the luteal phase.     

Mate guarding and frequent copulation in birds: A meta‐analysis of their relationship to paternity and male phenotype

In many birds, males are presumed to protect their paternity by closely guarding their mate or copulating frequently with her. Both these costly behaviors are assumed to reduce the risk and/or intensity of sperm competition. However, despite many studies on avian extra‐pair paternity, it remains unclear how strongly these behaviors are related to fitness and other key life‐history traits. Here, we conduct meta‐analyses to address two questions. First, are mate guarding and/or frequent copulation positively correlated with a male's share of paternity at his nest? We find a significant positive correlation between both presumed paternity protection behaviors and paternity share. The relationship is, however, weak (r = 0.08–0.23). This is perhaps unsurprising if the risk of partner infidelity, hence the need to protect paternity, varies among males. For example, more attractive males might have less need to protect their paternity. Second, do males with higher indices of so‐called male “quality” (phenotypic measures, usually subjectively defined by researchers as predictors of male attractiveness) exhibit lower levels of paternity protection behavior? We find a negative correlation between male quality and paternity protection. This finding might partly explain the weak relationship between paternity protection and paternity, although we discuss other, nonmutually exclusive possibilities.     

Intelligence and mate choice: intelligent men are always appealing

What role does a man's intelligence play in women's mate preferences? Selecting a more intelligent mate often provides women with better access to resources and parental investment for offspring. But this preference may also provide indirect genetic benefits in the form of having offspring who are in better physical condition, regardless of parental provisioning. Intelligence then may serve as both a cue of a mate's provisioning abilities and his overall heritable phenotypic quality. In the current study, we examined the role of a man's intelligence in women's long- and short-term mate preferences. We used a rigorous psychometric measure (men's WAIS scores) to assess intelligence (the first study to our knowledge), in addition to women's subjective ratings to predict mate appeal. We also examined the related trait of creativity, using women's ratings as a first step, to assess whether creativity could predict mate appeal, above and beyond intelligence. Finally, we examined whether preferences for intelligent and creative short-term mates shifted according to a woman's conception risk. Multilevel modeling was used to identify predictors of mate appeal. Study participants (204 women) assessed the long- and short-term mate appeal of videos of 15 men with known measures of intelligence performing verbal and physical tasks. Findings indicate that both intelligence and creativity independently predicted mate appeal across mating contexts, but no conception-risk effects were detected. We discuss implications of these findings for the role of intelligence and creativity in women's mate choices.     

Multiyear multiple paternity and mate fidelity in the American alligator, Alligator mississippiensis

We examined multiple paternity during eight breeding events within a 10-year period (1995–2005) for a total of 114 wild American alligator nests in Rockefeller Wildlife Refuge in south-west Louisiana. Our goals included examining (i) within population variation in multiple paternity among years, (ii) variation in multiple paternity in individual females and (iii) the potential for mate fidelity. To accomplish this, in the current study, eggs were sampled from 92 nests over 6 years and analysed along with 22 nests from a previous 2-year study. Genotypes at five microsatellite loci were generated for 1802 alligator hatchlings. Multiple paternity was found in 51% of clutches and paternal contributions to these clutches were highly skewed. Rates of multiple paternity varied widely among years and were consistently higher in the current study than previously reported for the same population. Larger females have larger clutches, but are not more likely to have multiply sired nests. However, small females are unlikely to have clutches with more than two sires. For 10 females, nests from multiple years were examined. Seven (70%) of these females exhibited long-term mate fidelity, with one female mating with the same male in 1997, 2002 and 2005. Five females exhibiting partial mate fidelity (71%) had at least one multiple paternity nest and thus mated with the same male, but not exclusively. These patterns of mate fidelity suggest a potential role for mate choice in alligators.     

Withholding Age as Putative Deception in Mate Search Tactics

Mate choice is a process of negotiation in which individuals make decisions about whether or not to allow a relationship with a prospective mate to develop into a long-term relationship. In some cases, this process begins with opening bids between strangers. Although each individual may have a clearly perceived set of preferred options, frequency-dependent effects and constraints on available search time often mean that individuals have to settle for less than ideal partners. Age is a criterion that males use in judging the mate value of prospective female partners, because it correlates with fertility. In this paper, we analyze personal advertisements to show that women may decline to declare their age in order to appear younger than they really are. This allows them to be more demanding than they would otherwise be able to be. A comparison of trait profiles with those of women of known age suggests that individuals who disguise their ages are likely to be in the age range 35 to 50 years. Three alternative explanations for this can be suggested: such behavior might be an attempt to find a high-quality partner (1) before their reproductive opportunities are foreclosed by menopause, (2) to replace lost paternal investment, or (3) to reduce the burden on the children of caring for aging parents by obtaining companionship and assistance from a new partner.     

Female differential allocation in response to extrapair offspring and social mate attractiveness

Renewed debate over what benefits females might gain from producing extra‐pair offspring emphasizes the possibility that apparent differences in quality between within‐pair and extra‐pair offspring are confounded by greater maternal investment in extra‐pair offspring. Moreover, the attractiveness of a female''s social mate can also influence contributions of both partners to a reproductive attempt. Here, we explore the complexities involved in parental investment decisions in response to extra‐pair offspring and mate attractiveness with a focus on the female point of view. Adult zebra finches paired and reproduced in a colony setting. A male''s early‐life diet quality and his extra‐pair reproductive success were used as metrics of his mating attractiveness. Females paired with males that achieved extra‐pair success laid heavier eggs than other females and spent less time attending their nests than their mates or other females. Extra‐pair nestlings were fed more protein‐rich hen''s egg than within‐pair nestlings. Females producing extra‐pair offspring had more surviving sons than females producing only within‐pair offspring. Collectively, results show that females differentially allocate resources in response to offspring extra‐pair status and their social mate''s attractiveness. Females may also obtain fitness benefits through the production of extra‐pair offspring.     

Faithful without care: the evolution of monogyny

The traditional paradigm of male polygamy and female monogamy has been replaced by the recognition that both sexes may typically mate with several partners. As a consequence, much attention has focused on the evolution of polyandry, while the evolutionary significance of monogyny (male monogamy) remains poorly understood. Monogyny, a taxonomically widespread mating system that includes dramatic examples of male self-sacrifice, is predicted when the benefits of paternal investment exceed those of searching for additional mates. However, monogyny also occurs in animals lacking paternal investment, instead representing a form of paternity protection. It has been suggested that such mating systems are expected where the costs of mate search for males are high. However, this argument fails to recognize that if there is a low probability of a male finding a mate, then there may be a high probability that he will not need to defend his paternity. Using a mathematical model, we show that monogyny as a means of increasing paternity is favored when the sex ratio is male biased, but not necessarily by high search costs. The importance of a male-biased sex ratio for the evolution of monogyny is supported by various empirical studies.     

Microsatellite analysis of sperm-use patterns in the bushcricket Requena verticalis

Abstract.— The proportion of offspring sired by the second male to mate with a doubly mated female, P2, is a ubiquitously measured statistic in the study of insect sperm competition. Nevertheless, the underlying mechanisms of sperm transfer, storage, and use that determine P2 are poorly understood. Typically the second male to mate gains moderate to high paternity. More rarely, the first male to mate gains the majority of fertilizations. Here we examine the transfer, storage, and use of sperm in the bushcricket Requena verticalis , a species with male parental investment and almost complete first male paternity. Sperm drain from an externally attached spermatophore into the female's reproductive tract, where they are transported to the sperm store or spermatheca. We find that only sperm from the first male to mate are transported to the spermatheca. We provide some data that address a number of different mechanisms that might account for the lack of storage of second-male sperm. DNA microsatellite markers are developed to assign paternity. By manipulating the numbers of sperm transferred by first and second males, we show that the size of the ejaculate transferred by the first male has a major impact on paternity; increasing ejaculate size of the first male assures his paternity. Paternity assurance in R. verticalis holds significant implications for the evolution of paternal investment via the male's nuptial gift.     

Physical violence against intimate partners and related exposures to violence among South African men

Background

Despite high rates of intimate partner violence in South Africa, there have been no national studies of men''s perpetration of violence against female partners.

Methods

We analyzed data from the South Africa Stress and Health Study, a cross-sectional, nationally representative study, specifically examining data for men who had ever been married or had ever cohabited with a female partner. We calculated the prevalence of physical violence against intimate female partners and used logistic regression to examine associations with physical abuse during childhood and exposure to parental and community violence.

Results

A total of 834 male participants in the South Africa Stress and Health Study met the study criteria. Of these, 27.5% reported using physical violence against their current or most recent female partner during their current or most recent marriage or cohabiting relationship. Crude odds ratios (ORs) and 95% confidence intervals (CIs) indicated significant associations between perpetration of violence against an intimate partner and witnessing parental violence (OR 3.91, 95% CI 2.66–5.73) or experiencing physical abuse during childhood (OR 3.24, 95% CI 2.27–4.63), but not exposure to community violence (OR 1.29, 95% CI 0.88–1.88). The 2 significant associations persisted in adjusted analyses: OR 3.22 (95% CI 1.94–5.33) for witnessing parental violence and OR 1.73 (95% CI 1.07–2.79) for experiencing physical abuse during childhood.

Interpretation

We found a high prevalence of physical violence perpetrated by men against their intimate partners. Men who experienced physical abuse during childhood or were exposed to parental violence were at the greatest risk.Most research about men''s perpetration of violence against female intimate partners has concentrated on elucidating the factors that put women at risk for experiencing such violence and identifying the related service needs. Less work has been done to investigate the factors affecting men''s risk of perpetrating violence against women. Such work is needed to inform development of empirically based public health programs to reduce men''s use of such violence. Intimate partner violence is of pandemic proportions, with global estimates indicating that 15% to 75% of women have experienced such abuse.^1,2 Such violence may confer grave health consequences, including transmission of HIV/AIDS.³The overwhelming majority of research on violence against intimate partners perpetrated by men has been conducted in Western countries, with the focus on men at high risk for such activity (e.g., prisoners, people enrolled in intervention programs for batterers).^4,5 This work has highlighted the importance of exposure to violence early in life (e.g., witnessing parental violence, experiencing child abuse) in predicting perpetration of violence against a partner during adulthood.⁶ Recently, the potential relations between community violence and men''s perpetration of violence against intimate partners have also been examined.⁷Fewer studies have been done in developing nations, but several notable investigations have recently assessed men''s perpetration of violence against intimate partners in South Africa, specifically in Eastern Cape and Cape Town. Two of these studies have indicated high rates of violence against intimate partners: 31.8% in Eastern Cape⁸ and 42.3% in Cape Town.⁹ The extent to which these findings reflect national rates is unknown. Furthermore, work with both men and women in South Africa has demonstrated strong relations between violence (men''s perpetration and women''s victimization) and higher rates of sexually risky behaviours.^3,8 Associations between women''s experience as victims of intimate partner violence and HIV infection have also been documented.³ These data strongly suggest that men''s perpetration of violence against intimate partners is common in South Africa and that it may play an important role in this nation''s HIV epidemic,^3,8 which currently ranks highest in the world with respect to the number of people living with HIV.¹⁰In the study reported here, we sought to build upon prior work by using a national sample of South African men to examine the prevalence of physical violence perpetrated by men against their female intimate partners and potential violence-related risk factors (i.e., exposure to parental violence, experience of abuse in childhood and exposure to community violence).     

Explicit experimental evidence for the role of mate guarding in minimizing loss of paternity in the Seychelles warbler

Extra-pair copulations (EPCs) (copulations outside the pair bond) resulting in extra-pair fertilizations (EPFs) are widespread in birds. To increase reproductive success, males should not only seek EPCs, but also prevent their females from having EPFs. Male Seychelles warblers (Acrocephalus sechellensis) follow their partner closely during the period when these females are most receptive (fertile period). The Seychelles warbler is the first species to offer explicit experimental evidence that mate guarding functions as paternity guarding: in territories where free-living males were induced to stop mate guarding during the pair female''s fertile period, the rates of intrusions by other males and successful EPCs (male mounting female) were significantly higher than those observed in the control group and in the absence of mate guarding the frequency of successful EPCs increased significantly with local male density. Male warblers do not assure their paternity through frequent copulations to devalue any sperm from other males: males do not copulate with their partners immediately following a successful EPC obtained by their partners, the frequency of successful within-pair copulations does not increase with the frequency of successful EPCs and females initiate all successful copulations and are capable of resisting copulation attempts.     

Genetic relatedness to sisters' children has been underestimated

Males of many species help in the care and provisioning of offspring, and these investments often correlate with genetic relatedness. For example, many human males invest in the children of sisters, and this is especially so where men are less likely to share genes with children of wives. Although this makes qualitative sense, it has been difficult to support quantitatively. The prevailing model predicts investment in children of sisters only when paternity confidence falls below 0.268. This value is often seen as too low to be credible; so investment in sisters'' children represents an unsolved problem. I show here that the prevailing model rests on a series of restrictive assumptions that underestimate relatedness to sisters'' children. For this reason, it understates the fitness payoff to men who invest in these children. This effect can be substantial, especially in societies with low confidence in paternity. But this effect cannot be estimated solely from confidence in paternity. One must also estimate the probability that two siblings share the same father.     

Confidence of paternity and paternal care: covariation revealed through the experimental manipulation of the mating system in the beetle Onthophagus taurus

Theoretical models of paternal care predict that facultative reductions in male care may occur under certain conditions. One important parameter that has been shown to influence the outcome of these models is a male's confidence of paternity. In this study, we tested whether the amount of care provided by horned males in the dimorphic beetle, Onthophagus taurus, varied with his confidence of paternity. Male care results in an increased weight of dung provided in the brood masses produced by the pair. Using the sterile male technique we showed that a horned male's paternity declined with the number of sneak males in the population. The relationship was nonlinear, with paternity declining most rapidly between a frequency of one and three sneaks, and stabilizing thereafter at about 50%. A horned male's paternity was directly related to the number of copulations with the female, relative to the number of copulations achieved by sneaks. Horned males were shown to reduce their care in relation to their declining paternity. Video analysis demonstrated that reductions in male care occurred through a combination of male desertion and a trade‐off between caring and paternity assurance behaviours. The number of fights with sneak males was negatively related to the amount of care provided by a horned male. These results suggest that by gauging his expected paternity through the number of fights with sneaks, a horned male is able to assess his paternity and reduce his investment accordingly. Our data thus provide strong empirical support for the proposed link between paternity and paternal care.     

Genetic and behavioural evidence of monogamy in a mammal,Kirk's dik-dik (Madoqua kirkii).

Little is known about the mating behaviour of monogamous mammals. Here, we present behavioural and genetic evidence of fidelity in a socially monogamous dwarf antelope, Kirk''s dik-dik. DNA microsatellite analysis revealed no evidence of extra-pair paternity (EPP) in dik-diks: mothers'' partners matched the paternal genotype in all 12 juveniles tested. One likely reason for the absence of EPP is that males guard their mates closely during oestrus and over-mark all female scent, thereby reducing the likelihood of other males attempting to mate. In addition, males may be limited in their ability to search for extra-pair populations (EPCs) by activities associated with pair-bond maintenance. Year-round, males maintained proximity within pairs, followed their females'' activity patterns, and spent approximately 64% of their time with their partners. However, males did attempt to obtain EPCs when the opportunity arose, and genetic monogamy in dik-diks is probably best explained by the behaviour of females: in contrast to many monogamous female birds, female dik-diks do not appear to seek EPC partners. We propose that females avoid extra-pair males because they are unable to mate with them without instigating a potentially dangerous conflict.     

Male burying beetles extend,not reduce,parental care duration when reproductive competition is high

Male parents spend less time caring than females in many species with biparental care. The traditional explanation for this pattern is that males have lower confidence of parentage, so they desert earlier in favour of pursuing other mating opportunities. However, one recent alternative hypothesis is that prolonged male parental care might also evolve if staying to care actively improves paternity. If this is the case, an increase in reproductive competition should be associated with increased paternal care. To test this prediction, we manipulated the level of reproductive competition experienced by burying beetles, Nicrophorus vespilloides (Herbst, 1783). We found that caregiving males stayed for longer and mated more frequently with their partner when reproductive competition was greater. Reproductive productivity did not increase when males extended care. Our findings provide support for the increased paternity hypothesis. Extended duration of parental care may be a male tactic both protecting investment (in the current brood) and maximizing paternity (in subsequent brood(s) via female stored sperm) even if this fails to maximize current reproductive productivity and creates conflict of interest with their mate via costs associated with increased mating frequency.     

Do male paternity guards ensure female fidelity in a duetting fairy-wren?

Most socially monogamous bird species engage in extra-pair mating,and consequently males may adopt various behavioral strategiesto guard paternity. However, the relationship between mate guardingand extra-pair paternity is unclear: low levels of extra-pairpaternity can be associated either with no mate guarding orwith intense mate guarding. We investigate paternity guardsin the purple-crowned fairy-wren (Malurus coronatus), a duettingspecies where extra-pair paternity is rare. This species isunusual in a genus known for extremely high levels of extra-pairmating. We examine the behavioral interactions between the sexesunderlying these low rates of extra-pair paternity and showthat male purple-crowned fairy-wrens do not use frequent copulationor courtship feeding to assure paternity or guard females acousticallyby duetting. Males maintain close proximity to females bothwhen they are fertile and when they are not breeding and donot invest in courtship displays to extra-pair females. Consistentwith predictions of theoretical models, low extra-pair paternityin this species may be related to female fidelity rather thanmale paternity assurance strategies, but short-term removalof males would be necessary to test this experimentally.