scholarly journals What do men want? Re-examining whether men benefit from higher fertility than is optimal for women

2016 ◽  
Vol 371 (1692) ◽  
pp. 20150149 ◽  
Author(s):  
Cristina Moya ◽  
Kristin Snopkowski ◽  
Rebecca Sear
Keyword(s):  
Sexual Conflict ◽  
Empirical Data ◽  
Conflicts Of Interest ◽  
Reproductive Decisions ◽  
Reproductive Timing ◽  
Reproductive Autonomy ◽  
Costs Of Reproduction ◽  
Male Preference ◽  
Sexual Conflicts ◽  
Fitness Consequences

Several empirical observations suggest that when women have more autonomy over their reproductive decisions, fertility is lower. Some evolutionary theorists have interpreted this as evidence for sexual conflicts of interest, arguing that higher fertility is more adaptive for men than women. We suggest the assumptions underlying these arguments are problematic: assuming that women suffer higher costs of reproduction than men neglects the (different) costs of reproduction for men; the assumption that men can repartner is often false. We use simple models to illustrate that (i) men or women can prefer longer interbirth intervals (IBIs), (ii) if men can only partner with wives sequentially they may favour shorter IBIs than women, but such a strategy would only be optimal for a few men who can repartner. This suggests that an evolved universal male preference for higher fertility than women prefer is implausible and is unlikely to fully account for the empirical data. This further implies that if women have more reproductive autonomy, populations should grow, not decline. More precise theoretical explanations with clearly stated assumptions, and data that better address both ultimate fitness consequences and proximate psychological motivations, are needed to understand under which conditions sexual conflict over reproductive timing should arise.

Male genes with nowhere to hide; sexual conflict in haplodiploids

2009 ◽  
Vol 59 (4) ◽  
pp. 403-415 ◽  
Author(s):  
Ken Kraaijeveld
Keyword(s):  
Gene Expression ◽  
Genomic Imprinting ◽  
Sexual Conflict ◽  
Empirical Data ◽  
Conflicts Of Interest ◽  
Conflict Theory ◽  
Male And Female ◽  
Number Of Factors ◽  
Dominance Interactions

AbstractConflicts of interest between male and females over reproduction and gene expression are thought to be widespread among animals. However, most research on sexual conflict focuses on diploid, bisexual organisms. It is not obvious that the role of sexual conflict is the same in diploids as in organisms with different reprodutive systems. Here, I consider the potential for evolutionary change through sexual conflict in haplodiploids. As very little sexual conflict theory has been developed specifically for haplodiploids, I rely on the analogy between haplodiploid reproduction and X-chromosomal inheritance. The main conclusions are that the opportunity for between-locus sexual conflict should be the same for haplodiploids as for diploids, provided that the sexually antagonistic alleles involved are sex-limited from when they first appear. Empirical data testing this hypothesis are almost non-existent. The dynamics of within-locus sexual conflict are likely to differ strongly between haplodiploid and autosomal diploid genes depending on the dominance interactions between male and female alleles. In general, it is expected that this type of conflict will often be resolved in favour of females in haplodiploids. A number of factors, such as genomic imprinting and lack of recombination between male and female genomes may prevent this outcome.

scholarly journals Fitness consequences of divorce in the azure-winged magpie depends on the breeding experience of a new mate

2020 ◽  
Author(s):  
Li-Fang Gao ◽  
Hai-Yang Zhang ◽  
Wen Zhang ◽  
Xiao-Dan Zhang ◽  
Zhen-Qin Zhu ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Sexual Conflict ◽  
Evolutionary Ecology ◽  
Critical Issue ◽  
Breeding Performance ◽  
Breeding Experience ◽  
Sexual Conflicts ◽  
Fitness Consequences ◽  
Fitness Consequence ◽  
Future Reproduction

Abstract Sexual conflict in producing and raising offspring is a critical issue in evolutionary ecology research. Individual experience affects their breeding performance, as measured by such traits of provisioning of offspring and engagement in extra-pair copulations, and may cause an imbalance in sexual conflict. Thus, divorce is hypothesized to occur within aged social pairs, irrespective of current reproductive success. This concept was explored in the azure-winged magpie Cyanopica cyanus by investigating the divorce of a social pair and its relationship to their changes in breeding performance with prior experience. Females engaging in extra-pair copulation may intensify sexual conflicts and may be the main reason for divorce. Once divorced, females repairing with an inexperienced male realized higher reproductive success than that repairing with an experienced male; males repairing with an experienced female realized higher reproductive success than that repairing with an inexperienced female. This finding indicates that the fitness consequence of divorce depends on the breeding experience of new mates. Divorced females can obtain more extra-pair copulations, whereas divorced males cannot, when they repair with inexperienced breeders. Divorced females provisioned a brood at lower rates than inexperienced females whereas divorced males had no such difference. It appears that divorced females can obtain an advantage in sexual conflicts with inexperienced mates in future reproduction. Consequently, females are probably more active than males in divorcing their aged mates so as to select an inexperienced male as a new mate. Azure-winged magpies thus provide novel insights into the implications of sexual conflict in birds.

Prenatal Genetic Screening, Epistemic Justice, and Reproductive Autonomy

Hypatia ◽  
2021 ◽  
Vol 36 (1) ◽  
pp. 1-21
Author(s):  
Amber Knight ◽  
Joshua Miller
Keyword(s):  
Prenatal Testing ◽  
Relevant Information ◽  
Medical Professionals ◽  
Reproductive Decisions ◽  
Reproductive Autonomy ◽  
Noninvasive Prenatal Testing ◽  
Epistemic Justice ◽  
Reproductive Decision Making ◽  
Testimonial Injustice ◽  
And Control

AbstractNoninvasive prenatal testing (NIPT) promises to enhance women's reproductive autonomy by providing genetic information about the fetus, especially in the detection of genetic impairments like Down syndrome (DS). In practice, however, NIPT provides opportunities for intensified manipulation and control over women's reproductive decisions. Applying Miranda Fricker's concept of epistemic injustice to prenatal screening, this article analyzes how medical professionals impair reproductive decision-making by perpetuating testimonial injustice. They do so by discrediting positive parental testimony about what it is like to raise a child with DS. We argue that this testimonial injustice constitutes a twofold harm: (1) people with DS and their family members who claim that parenting a child with DS may be a rewarding and joyous experience are harmed when they are systematically silenced, disbelieved, and/or denied epistemic credibility by medical professionals, and (2) pregnant women are harmed since they might make poorly informed choices without access to all relevant information. The broader implication of the analysis is that epistemic justice is a precondition of reproductive autonomy. We conclude by calling for federal oversight of the acquisition and dissemination of information that prospective parents receive following a positive diagnosis of DS to ensure that it is comprehensive and up to date.

scholarly journals Overinvestment and underinvestment problems: determining factors, consequences and solutions

2007 ◽  
Vol 5 (1) ◽  
pp. 79-95 ◽  
Author(s):  
Maurizio La Rocca ◽  
Elvira Tiziana La Rocca ◽  
Alfio Cariola
Keyword(s):  
Corporate Governance ◽  
Capital Structure ◽  
Empirical Data ◽  
Conflicts Of Interest ◽  
Investment Policies ◽  
Managerial Decisions ◽  
Production Processes ◽  
Determining Factors ◽  
Value Production ◽  
Firm Governance

The potential conflicts of interest between managers, stockholders and debtholders influence capital structure, corporate governance activities and investment policies, which, in turn, could give rise to inefficient managerial decisions and “suboptimal” investments that generally fall under the categories of problems of underinvestment and overinvestment. This paper intends to discuss these problems by identifying their causes, determining factors and the consequences on the value production processes, as well as to point out possible solutions to them. After having confronted the effects and their implications on firm governance activities by clarifying the relevance of the phenomenon and showing the main empirical data that emerged in the prevailing researches, we summarize the main financial proposals found in literature that can diminish their impact

scholarly journals Age-dependent female responses to a male ejaculate signal alter demographic opportunities for selection

2013 ◽  
Vol 280 (1766) ◽  
pp. 20130428 ◽  
Author(s):  
Claudia Fricke ◽  
Darrell Green ◽  
Walter E. Mills ◽  
Tracey Chapman
Keyword(s):  
Sexual Conflict ◽  
Seminal Fluid ◽  
Conflicts Of Interest ◽  
Egg Laying ◽  
Specific Expression ◽  
Young Females ◽  
Sexually Selected Traits ◽  
Selected Traits ◽  
Female Responses ◽  
Seminal Fluid Protein

A central tenet of evolutionary explanations for ageing is that the strength of selection wanes with age. However, data on age-specific expression and benefits of sexually selected traits are lacking—particularly for traits subject to sexual conflict. We addressed this by using as a model the responses of Drosophila melanogaster females of different ages to receipt of sex peptide (SP), a seminal fluid protein transferred with sperm during mating. SP can mediate sexual conflict, benefitting males while causing fitness costs in females. Virgin and mated females of all ages showed significantly reduced receptivity in response to SP. However, only young virgin females also showed increased egg laying; hence, there was a narrow demographic window of maximal responses to SP. Males gained significant ‘per mating’ fitness benefits only when mating with young females. The pattern completely reversed in matings with older females, where SP transfer was costly. The overall benefits of SP transfer (hence opportunity for selection) therefore reversed with female age. The data reveal a new example of demographic variation in the strength of selection, with convergence and conflicts of interest between males and ageing females occurring over different facets of responses to a sexually antagonistic trait.

Trade-Offs and Carry-Over Effects

2012 ◽  
Author(s):  
Tony D. Williams
Keyword(s):  
Point Of View ◽  
Breeding Period ◽  
Reproductive Decisions ◽  
Costs Of Reproduction ◽  
Life History Stages ◽  
Complete Life Cycle ◽  
Trade Offs ◽  
Term Energy ◽  
Carry Over ◽  
Underlying Mechanisms

This chapter first reviews the evidence for interactions between life-history stages, centering this around reproduction itself: the intention is to put reproduction in the context of the complete life-cycle. It considers how the wintering and pre-breeding period, including spring migration, can influence reproductive decisions, and in turn how reproductive decisions can influence subsequent post-breeding life stages such as molt, fall migration, and over-winter survival. It looks at the costs of reproduction, simply as a more specific example of general carry-over effects, especially from a mechanistic point of view, with potentially common underlying mechanisms. The chapter argues that short-term energy or nutrient “debts” and resource-allocation trade-offs provide unsatisfactory models for long-term carry-over effects or costs of reproduction; instead, it emphasizes potential “non-resource based” mechanisms.

scholarly journals Flexibility in reproductive timing in human females: integrating ultimate and proximate explanations

2011 ◽  
Vol 366 (1563) ◽  
pp. 357-365 ◽  
Author(s):  
Daniel Nettle
Keyword(s):  
Age Of Onset ◽  
Mortality Rates ◽  
Age At First Birth ◽  
Reproductive Decisions ◽  
Reproductive Timing ◽  
Female Reproduction ◽  
Healthy Life ◽  
Proximate Mechanisms ◽  
Reproductive Activities ◽  
Cross National

From an ultimate perspective, the age of onset of female reproduction should be sensitive to variation in mortality rates, and variation in the productivity of non-reproductive activities. In accordance with this prediction, most of the cross-national variation in women's age at first birth can be explained by differences in female life expectancies and incomes. The within-country variation in England shows a similar pattern: women have children younger in neighbourhoods where the expectation of healthy life is shorter and incomes are lower. I consider the proximate mechanisms likely to be involved in producing locally appropriate reproductive decisions. There is evidence suggesting that developmental induction, social learning and contextual evocation may all play a role.

FEMALE-FEMALE CONFLICT IN THE HAREM OF A SNAIL CICHLID (LAMPROLOGUS OCELLATUS): BEHAVIOURAL INTERACTIONS AND FITNESS CONSEQUENCES

Behaviour ◽  
1999 ◽  
Vol 136 (9) ◽  
pp. 1123-1144 ◽  
Author(s):  
Fritz Trillmich ◽  
Gesine Brandtmann ◽  
Massimo Scandura
Keyword(s):  
Lake Tanganyika ◽  
Size Difference ◽  
Sexual Competition ◽  
Male Preference ◽  
Young Females ◽  
Simultaneous Choice ◽  
Fitness Consequences ◽  
Choice Tests ◽  
Microsatellite Length Polymorphism ◽  
Behavioural Interactions

AbstractFemale intra-sexual competition plays an important role in the settlement process during pair or harem formation and in established harems of Lamprologus ocellatus , a small snail shell inhabiting cichlid from Lake Tanganyika. Larger females settle first and this could partly be due to male preference for larger females as shown in simultaneous choice tests but is also due to dominance of the larger female. Smaller females were unable to settle close to a larger one. Even when snail shells were not limiting the smaller was either unable to settle or had to settle at a considerable distance. This effect was independent of prior residence. Intense female-female aggression suggests that close settlement is disadvantageous to females. Genetic analyses of maternity using microsatellite length polymorphism at five loci showed a reproductive skew between females in a harem. Additionally, it proved brood mixing in aquaria as well as in the field. Brood mixing can be detrimental to female breeding success through interbrood cannibalism if size difference of juveniles amounts to 5 mm. Territoriality of juveniles, shown even between same-sized siblings, may cause indirect mortality through earlier dispersal of young. Females rejected experimentally added larger juveniles but accepted young smaller than their own fry. Acceptance of smaller juveniles could be advantageous through a dilution of predator attacks but it also appears to induce costs since females with young at the shell do not rear another brood. Large median distances of 91 cm maintained aggressively between breeding females in the field may serve to minimize the adverse effects of breeding in a harem.

Sexual Selection and Sexual Conflict in Crustaceans

2020 ◽  
pp. 305-331
Author(s):  
Rickey Cothran
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Sexual Conflict ◽  
Sensory System ◽  
Mate Guarding ◽  
Female Mate Choice ◽  
Female Mate ◽  
Fitness Consequences ◽  
Sensory Structures ◽  
Context Shapes

Research using crustaceans has improved the understanding of sexual selection and sexual conflict. This is particularly true for understanding the biology of male weaponry and sexual conflict over mate guarding. Male crustaceans often are equipped with exaggerated claws that they use to monopolize access to females or resources that females use for reproduction. However, these weapons are often used in other contexts, e.g. mate choice and coercion of females, and understanding their evolution requires a broader perspective of how these traits are built and the fitness consequences of their use for both the bearer and interacting individuals. Although less well studied than male weaponry, crustaceans also provide excellent examples of elaborate sensory structures that are used in scramble competition among males for females. In addition to studies on male-male competition, crustaceans have been well represented in research on intrasexual selection (for the most part, female mate choice). Crustacean females use a variety of sensory channels to assess mates, and a challenge is to better understand what is being conveyed by signaling males and the fitness consequences of mate choice for females. In some cases the female’s sensory system appears to be exploited by males, and this could lead to sexual conflict over mating. Research on crustaceans has also informed the understanding of sexual conflict over mate guarding, including the evolution of traits used to resolve conflict and how the ecological context shapes the costs and benefits of guarding for both sexes.

Revisiting Minors’ Reproductive Autonomy Rights under South African Law: The Rights and Wrongs of the Choice on Termination of Pregnancy Act

2018 ◽  
Vol 33 (1) ◽  
Author(s):  
Admark Moyo
Keyword(s):  
Decision Making ◽  
South African ◽  
State Intervention ◽  
Termination Of Pregnancy ◽  
Reproductive Decisions ◽  
Reproductive Autonomy ◽  
Parental Responsibility ◽  
Reproductive Decision ◽  
Reproductive Decision Making ◽  
The Right

This article examines the interface between children’s autonomy, parental responsibility and state intervention in reproductive decisions of a particular type, namely the termination of pregnancy. Children asserting their autonomy in reproductive decision-making often confront counterclaims of legitimate intervention by parents or guardians responsible for caring for the child. Locating the right balance between competing interests is very important because uninformed decisions, with or without the support of parents, often carry heavy consequences for the education, health and life of the pregnant child. More specifically, this article seeks to investigate the extent to which South African law protects and empowers sexually active adolescents to make decisions concerning the termination of pregnancy. This involves an analysis of the degree to which relevant legislation appropriately reconciles children’s reproductive autonomy rights–—particularly the right to terminate a pregnancy without parental consent or approval–—with parental responsibility and state intervention. Parental responsibility and state intervention embody children’s right to and need for protection (from the immaturity that characterises youth) when decisions to terminate pregnancies are made. Accordingly, this article focuses on whether or not the Choice on Termination of Pregnancy Act strikes an appropriate balance between children’s autonomy, parental responsibility and state intervention in reproductive decision-making.

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