Sample records for survival sexual selection
-
Nieuwenhuis, B.P.S.
2012-01-01
Sexual selection is an important factor that drives evolution, in which fitness is increased, not by increasing survival or viability, but by acquiring more or better mates. Sexual selection favours traits that increase the ability of an individual to obtain more matings than other individuals
-
Sexual selection protects against extinction.
Lumley, Alyson J; Michalczyk, Łukasz; Kitson, James J N; Spurgin, Lewis G; Morrison, Catriona A; Godwin, Joanne L; Dickinson, Matthew E; Martin, Oliver Y; Emerson, Brent C; Chapman, Tracey; Gage, Matthew J G
2015-06-25
Reproduction through sex carries substantial costs, mainly because only half of sexual adults produce offspring. It has been theorized that these costs could be countered if sex allows sexual selection to clear the universal fitness constraint of mutation load. Under sexual selection, competition between (usually) males and mate choice by (usually) females create important intraspecific filters for reproductive success, so that only a subset of males gains paternity. If reproductive success under sexual selection is dependent on individual condition, which is contingent to mutation load, then sexually selected filtering through 'genic capture' could offset the costs of sex because it provides genetic benefits to populations. Here we test this theory experimentally by comparing whether populations with histories of strong versus weak sexual selection purge mutation load and resist extinction differently. After evolving replicate populations of the flour beetle Tribolium castaneum for 6 to 7 years under conditions that differed solely in the strengths of sexual selection, we revealed mutation load using inbreeding. Lineages from populations that had previously experienced strong sexual selection were resilient to extinction and maintained fitness under inbreeding, with some families continuing to survive after 20 generations of sib × sib mating. By contrast, lineages derived from populations that experienced weak or non-existent sexual selection showed rapid fitness declines under inbreeding, and all were extinct after generation 10. Multiple mutations across the genome with individually small effects can be difficult to clear, yet sum to a significant fitness load; our findings reveal that sexual selection reduces this load, improving population viability in the face of genetic stress.
-
The effect of sexual selection on adaptation and extinction under increasing temperatures.
Parrett, Jonathan M; Knell, Robert J
2018-04-25
Strong sexual selection has been reported to both enhance and hinder the adaptive capacity and persistence of populations when exposed to novel environments. Consequently, how sexual selection influences population adaption and persistence under stress remains widely debated. Here, we present two empirical investigations of the fitness consequences of sexual selection on populations of the Indian meal moth, Plodia interpunctella, exposed to stable or gradually increasing temperatures. When faced with increasing temperatures, strong sexual selection was associated with both increased fecundity and offspring survival compared with populations experiencing weak sexual selection, suggesting sexual selection acts to drive adaptive evolution by favouring beneficial alleles. Strong sexual selection did not, however, delay extinction when the temperature became excessively high. By manipulating individuals' mating opportunities during fitness assays, we were able to assess the effect of multiple mating independently from the effect of population-level sexual selection, and found that polyandry has a positive effect on both fecundity and offspring survival under increasing temperatures in those populations evolving with weak sexual selection. Within stable temperatures, there were some benefits from strong sexual selection but these were not consistent across the entire experiment, possibly reflecting changing costs and benefits of sexual selection under stabilizing and directional selection. These results indicate that sexual selection can provide a buffer against climate change and increase adaptation rates within a continuously changing environment. These positive effects of sexual selection may, however, be too small to protect populations and delay extinction when environmental changes are relatively rapid. © 2018 The Author(s).
-
The relationship between sexual selection and sexual conflict.
Kokko, Hanna; Jennions, Michael D
2014-07-18
Evolutionary conflicts of interest arise whenever genetically different individuals interact and their routes to fitness maximization differ. Sexual selection favors traits that increase an individual's competitiveness to acquire mates and fertilizations. Sexual conflict occurs if an individual of sex A's relative fitness would increase if it had a "tool" that could alter what an individual of sex B does (including the parental genes transferred), at a cost to B's fitness. This definition clarifies several issues: Conflict is very common and, although it extends outside traits under sexual selection, sexual selection is a ready source of sexual conflict. Sexual conflict and sexual selection should not be presented as alternative explanations for trait evolution. Conflict is closely linked to the concept of a lag load, which is context-dependent and sex-specific. This makes it possible to ask if one sex can "win." We expect higher population fitness if females win. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.
-
Andersson, Malte
2004-01-01
Sexual selection in the form of sperm competition is a major explanation for small size of male gametes. Can sexual selection in polyandrous species with reversed sex roles also lead to reduced female gamete size? Comparative studies show that egg size in birds tends to decrease as a lineage evolves social polyandry. Here, a quantitative genetic model predicts that female scrambles over mates lead to evolution of reduced female gamete size. Increased female mating success drives the evolution of smaller eggs, which take less time to produce, until balanced by lowered offspring survival. Mean egg size is usually reduced and polyandry increased by increasing sex ratio (male bias) and maximum possible number of mates. Polyandry also increases with the asynchrony (variance) in female breeding start. Opportunity for sexual selection increases with the maximum number of mates but decreases with increasing sex ratio. It is well known that parental investment can affect sexual selection. The model suggests that the influence is mutual: owing to a coevolutionary feedback loop, sexual selection in females also shapes initial parental investment by reducing egg size. Feedback between sexual selection and parental investment may be common.
-
Sexual selection: Another Darwinian process.
Gayon, Jean
2010-02-01
Why was sexual selection so important to Darwin? And why was it de-emphasized by almost all of Darwin's followers until the second half of the 20th century? These two questions shed light on the complexity of the scientific tradition named "Darwinism". Darwin's interest in sexual selection was almost as old as his discovery of the principle of natural selection. From the beginning, sexual selection was just another "natural means of selection", although different from standard "natural selection" in its mechanism. But it took Darwin 30 years to fully develop his theory, from the early notebooks to the 1871 book The Descent of Man, and Selection in Relation to Sex. Although there is a remarkable continuity in his basic ideas about sexual selection, he emphasized increasingly the idea that sexual selection could oppose the action of natural selection and be non adaptive. In time, he also gave more weight to mate choice (especially female choice), giving explicit arguments in favor of psychological notions such as "choice" and "aesthetic sense". But he also argued that there was no strict demarcation line between natural and sexual selection, a major difficulty of the theory from the beginning. Female choice was the main reason why Alfred Russel Wallace, the co-discoverer of the principle of natural selection, engaged in a major controversy with Darwin about sexual selection. Wallace was suspicious about sexual selection in general, trying to minimize it by all sorts of arguments. And he denied entirely the existence of female choice, because he thought that it was both unnecessary and an anthropomorphic notion. This had something to do with his spiritualist convictions, but also with his conception of natural selection as a sufficient principle for the evolutionary explanation of all biological phenomena (except for the origin of mind). This is why Wallace proposed to redefine Darwinism in a way that excluded Darwin's principle of sexual selection. The main result of
-
Signal trait sexual dimorphism and mutual sexual selection in Drosophila serrata.
Chenoweth, Stephen F; Blows, Mark W
2003-10-01
The evolution of sexual dimorphism may occur when natural and sexual selection result in different optimum trait values for males and females. Perhaps the most prominent examples of sexual dimorphism occur in sexually selected traits, for which males usually display exaggerated trait levels, while females may show reduced expression of the trait. In some species, females also exhibit secondary sexual traits that may either be a consequence of a correlated response to sexual selection on males or direct sexual selection for female secondary sexual traits. In this experiment, we simultaneously measure the intersex genetic correlations and the relative strength of sexual selection on males and females for a set of cuticular hydrocarbons in Drosophila serrata. There was significant directional sexual selection on both male and female cuticular hydrocarbons: the strength of sexual selection did not differ among the sexes but males and females preferred different cuticular hydrocarbons. In contrast with many previous studies of sexual dimorphism, intersex genetic correlations were low. The evolution of sexual dimorphism in D. serrata appears to have been achieved by sex-limited expression of traits controlled by genes on the X chromosome and is likely to be in its final stages.
-
Antagonistic natural and sexual selection on wing shape in a scrambling damselfly.
Outomuro, David; Söderquist, Linus; Nilsson-Örtman, Viktor; Cortázar-Chinarro, María; Lundgren, Cecilia; Johansson, Frank
2016-07-01
Wings are a key trait underlying the evolutionary success of birds, bats, and insects. For over a century, researchers have studied the form and function of wings to understand the determinants of flight performance. However, to understand the evolution of flight, we must comprehend not only how morphology affects performance, but also how morphology and performance affect fitness. Natural and sexual selection can either reinforce or oppose each other, but their role in flight evolution remains poorly understood. Here, we show that wing shape is under antagonistic selection with regard to sexual and natural selection in a scrambling damselfly. In a field setting, natural selection (survival) favored individuals with long and slender forewings and short and broad hindwings. In contrast, sexual selection (mating success) favored individuals with short and broad forewings and narrow-based hindwings. Both types of selection favored individuals of intermediate size. These results suggest that individuals face a trade-off between flight energetics and maneuverability and demonstrate how natural and sexual selection can operate in similar directions for some wing traits, that is, wing size, but antagonistically for others, that is, wing shape. Furthermore, they highlight the need to study flight evolution within the context of species' mating systems and mating behaviors. © 2016 The Author(s).
-
Parker, Geoff A
2014-08-21
After brief historic overviews of sexual selection and sexual conflict, I argue that pre-ejaculatory sexual selection (the form of sexual selection discussed by Darwin) arose at a late stage in an inevitable succession of transitions flowing from the early evolution of syngamy to the evolution of copulation and sex roles. If certain conditions were met, this "sexual cascade" progressed inevitably, if not, sexual strategy remained fixed at a given stage. Prolonged evolutionary history of intense sperm competition/selection under external fertilization preceded the rise of advanced mobility, which generated pre-ejaculatory sexual selection, followed on land by internal fertilization and reduced sperm competition in the form of postcopulatory sexual selection. I develop a prospective model of the early evolution of mobility, which, as Darwin realized, was the catalyst for pre-ejaculatory sexual selection. Stages in the cascade should be regarded as consequential rather than separate phenomena and, as such, invalidate much current opposition to Darwin-Bateman sex roles. Potential for sexual conflict occurs throughout, greatly increasing later in the cascade, reaching its peak under precopulatory sexual selection when sex roles become highly differentiated. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.
-
Immune-mediated change in the expression of a sexual trait predicts offspring survival in the wild.
Directory of Open Access Journals (Sweden)
Rémi Chargé
Full Text Available BACKGROUND: The "good genes" theory of sexual selection postulates that females choose mates that will improve their offspring's fitness through the inheritance of paternal genes. In spite of the attention that this hypothesis has given rise to, the empirical evidence remains sparse, mostly because of the difficulties of controlling for the many environmental factors that may covary with both the paternal phenotype and offspring fitness. Here, we tested the hypothesis that offspring sired by males of a preferred phenotype should have better survival in an endangered bird, the houbara bustard (Chlamydotis undulata undulata. METHODOLOGY/PRINCIPAL FINDINGS: We tested if natural and experimentally-induced variation in courtship display (following an inflammatory challenge predicts the survival of offspring. Chicks were produced by artificial insemination of females, ensuring that any effect on survival could only arise from the transfer of paternal genes. One hundred and twenty offspring were equipped with radio transmitters, and their survival monitored in the wild for a year. This allowed assessment of the potential benefits of paternal genes in a natural setting, where birds experience the whole range of environmental hazards. Although natural variation in sire courtship display did not predict offspring survival, sires that withstood the inflammatory insult and maintained their courtship activity sired offspring with the best survival upon release. CONCLUSIONS: This finding is relevant both to enlighten the debate on "good genes" sexual selection and the management of supportive breeding programs.
-
Tibbetts, Elizabeth A; Forrest, Taylor; Vernier, Cassondra; Jinn, Judy; Madagame, Andrew
2015-11-01
Many animals have ornaments that mediate choice and competition in social and sexual contexts. Individuals with elaborate sexual ornaments typically have higher fitness than those with less elaborate ornaments, but less is known about whether socially selected ornaments are associated with fitness. Here, we test the relationship between fitness and facial patterns that are a socially selected signal of fighting ability in Polistes dominula wasps. We found wasps that signal higher fighting ability have larger nests, are more likely to survive harsh winters, and obtain higher dominance rank than wasps that signal lower fighting ability. In comparison, body weight was not associated with fitness. Larger wasps were dominant over smaller wasps, but showed no difference in nest size or survival. Overall, the positive relationship between wasp facial patterns and fitness indicates that receivers can obtain diverse information about a signaler's phenotypic quality by paying attention to socially selected ornaments. Therefore, there are surprisingly strong parallels between the information conveyed by socially and sexually selected signals. Similar fitness relationships in social and sexually selected signals may be one reason it can be difficult to distinguish the role of social versus sexual selection in ornament evolution. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.
-
Sexual selection protects against extinction
Lumley, Alyson; Michalczyk, Lukasz; Kitson, James; Spurgin, Lewis; Morrison, Catriona; Godwin, Joanne; Dickinson, Matthew; Martin, Oliver; Emerson, Brent; Chapman, Tracey; Gage, Matthew
2015-01-01
Reproduction through sex carries substantial costs, mainly because only half of sexual adults produce offspring. It has been theorised that these costs could be countered if sex allows sexual selection to clear the universal fitness constraint of mutation load. Under sexual selection, competition between (usually) males, and mate choice by (usually) females create important intraspecific filters for reproductive success, so that only a subset of males gains paternity. If reproductive success ...
-
Sexual Selection and Adaptation to Novel Environments
Martinossi-Allibert, Ivain
2017-01-01
The work included in this thesis aims at exploring the environmental sensitivity of benefits and costs of sexual selection through a combined empirical and theoretical effort, to increase our understanding of the impact of environmental change on sexually reproducing populations.Can sexual selection promote adaptation to novel environments? Sexual selection for good genes should accelerate adaptation by granting higher reproductive success to individuals of high genetic quality. However, sexu...
-
Sexual selection and hermaphroditic organisms: Testing theory
Directory of Open Access Journals (Sweden)
Janet L. LEONARD
2013-08-01
Full Text Available Sexual selection is widespread if not ubiquitous in hermaphroditic organisms. Although many phenomena that have been described as sexual selection in gonochores, (e.g. harem polygamy, multiple mating, elaborate courtship, even secondary sexual characters can be found in some hermaphrodites, what is more interesting is the ways in which sexual selection in hermaphrodites may differ from dioecious taxa. In hermaphrodites, an individual’s mating success includes its success from both sexual roles. Secondly, in many simultaneously hermaphroditic taxa there is strong evidence of sexual selection and yet the operational sex ratio is 1:1, by definition. Many simultaneous hermaphrodites have elaborate courtship and genital anatomy, suggesting sexual selection plays an important role in reproductive success. Sperm competition and cryptic female choice mean that the number of mates acquired is not necessarily a predictor of reproductive success. Even in simultaneous hermaphrodites with reciprocal mating, variance in reproductive success through the male role and through the female role may differ in a population. Moreover hermaphrodites may choose to emphasize one sexual role over the other. Data suggest that the preferred role varies in hermaphrodites, which creates an opportunity to test fundamental predictions and assumptions of sexual selection theory. Hermaphrodites may vary their emphasis on one sexual role over the other either developmentally or behaviorally in response to environmental or social parameters. How they use this capability in acquiring more or higher quality mates still requires study [Current Zoology 59 (4: 579–588, 2013].
-
Crudgington, Helen S; Beckerman, Andrew P; Brüstle, Lena; Green, Kathleen; Snook, Rhonda R
2005-05-01
Sexual conflict over reproduction can occur between males and females. In several naturally promiscuous insect species, experimental evolution studies that have enforced monogamy found evidence for sexual conflict. Here, we subjected the naturally promiscuous, sperm-heteromorphic fruit fly Drosophila pseudoobscura to enforced monogamy, standard levels of promiscuity, and elevated opportunities for promiscuity in four replicate lines. We examined the effect of male and female selection history and the proximate effect of variation in male density on female fitness parameters. We found that male density rather than male selection history explained a greater degree of female fecundity, egg hatching success, and productivity. Additionally, females selected under elevated promiscuity had greater fecundity and hatching success than did enforced monogamy females. Selection line males do not differ in their capacity to coerce females to remate, suggesting no divergence in precopulatory manipulative ability. However, these males did vary in their ability to suppress female remating, suggesting postcopulatory manipulation. These results indicate that sexual conflict can be manifested through both the proximate effects of male density and the historical levels of sexual selection and that the sexes respond differentially to these factors and further stress the multifarious channels of sexual communication that contribute to fitness.
-
Sexual selection, germline mutation rate and sperm competition
Directory of Open Access Journals (Sweden)
Møller AP
2003-04-01
Full Text Available Abstract Background An important component of sexual selection arises because females obtain viability benefits for their offspring from their mate choice. Females choosing extra-pair fertilization generally favor males with exaggerated secondary sexual characters, and extra-pair paternity increases the variance in male reproductive success. Furthermore, females are assumed to benefit from 'good genes' from extra-pair sires. How additive genetic variance in such viability genes is maintained despite strong directional selection remains an evolutionary enigma. We propose that sexual selection is associated with elevated mutation rates, changing the balance between mutation and selection, thereby increasing variance in fitness and hence the benefits to be obtained from good genes sexual selection. Two hypotheses may account for such elevated mutation: (1 Increased sperm production associated with sperm competition may increase mutation rate. (2 Mutator alleles increase mutation rates that are revealed by the expression of condition-dependent secondary sexual characters used by choosy females during their mate choice. M Petrie has independently developed the idea that mutator alleles may account for the maintenance of genetic variation in viability despite strong directional selection. Results A comparative study of birds revealed a positive correlation between mutation rate at minisatellite loci and extra-pair paternity, but not between mutation rate and relative testes mass which is a measure of relative sperm production. Minisatellite mutation rates were not related to longevity, suggesting a meiotic rather than a mitotic origin of mutations. Conclusion We found evidence of increased mutation rate in species with more intense sexual selection. Increased mutation was not associated with increased sperm production, and we suggest that species with intense sexual selection may maintain elevated mutation rates because sexual selection continuously
-
Environmental change disrupts communication and sexual selection in a stickleback population.
Candolin, Ulrika; Tukiainen, Iina; Bertell, Elina
2016-04-01
Environmental change that disrupts communication during mate choice and alters sexual selection could influence population dynamics. Yet little is known about such long-term effects. We investigated experimentally the consequences that disrupted visual communication during mate choice has for the quantity and viability of offspring produced in a threespine stickleback population (Gasterosteus aculeatus). We further related the results to long-term monitoring of population dynamics in the field to determine if changes are apparent under natural conditions. The results show that impaired visual communication because of algal blooms reduces reliability of male visual signals as indicators of offspring survival during their first weeks of life. This relaxes sexual selection but has no effect on the number of offspring hatching, as most males have a high hatching success in turbid water. Despite eutrophication and high turbidity levels that interfere with communication during mate choice, the population has grown during recent decades. Large numbers of offspring hatching, combined with high variation in juvenile fitness, has probably shifted selection to later life history stages and maintained a viable population. Together with reduced cost of sexual selection and ongoing ecosystem changes caused by human activities, this could have promoted population growth. These results point to the complexity of ecosystems and the necessity to consider all influencing factors when attempting to understand impacts of human activities on populations.
-
Sexually selected females in the monogamous Western Australian seahorse.
Kvarnemo, Charlotta; Moore, Glenn I; Jones, Adam G
2007-02-22
Studies of sexual selection in monogamous species have hitherto focused on sexual selection among males. Here, we provide empirical documentation that sexual selection can also act strongly on females in a natural population with a monogamous mating system. In our field-based genetic study of the monogamous Western Australian seahorse, Hippocampus subelongatus, sexual selection differentials and gradients show that females are under stronger sexual selection than males: mated females are larger than unmated ones, whereas mated and unmated males do not differ in size. In addition, the opportunity for sexual selection (variance in mating success divided by its mean squared) for females is almost three times that for males. These results, which seem to be generated by a combination of a male preference for larger females and a female-biased adult sex ratio, indicate that substantial sexual selection on females is a potentially important but under-appreciated evolutionary phenomenon in monogamous species.
-
Why are sexually selected weapons almost absent in females?
Directory of Open Access Journals (Sweden)
Anders BERGLUND
2013-08-01
Full Text Available In sex role reversed species, predominantly females evolve sexually selected traits, such as ornaments and/or weapons. Female ornaments are common and their function well documented in many species, whether sex role reversed or not. However, sexually selected female weapons seem totally absent except for small wing spurs in three jacana species, present in both males and females. This poor female weaponry is in sharp contrast to the situation in species with conventional sex roles: males commonly have evolved sexually selected weapons as well as ornaments. At the same time, females in many taxa have naturally selected weapons, used in competition over resources or in predator defence. Why are sexually selected weapons then so rare, almost absent, in females? Here I briefly review weaponry in females and the function of these weapons, conclude that the near absence of sexually selected weapons begs an explanation, and suggest that costs of sexually selected weapons may exceed costs of ornaments. Females are more constrained when evolving sexually selected traits compared to males, at least compared to those males that do not provide direct benefits, as trait costs reduce a female’s fecundity. I suggest that this constraining trade-off between trait and fecundity restricts females to evolve ornaments but rarely weapons. The same may apply to paternally investing males. Whether sexually selected weapons actually are more costly than sexually selected ornaments remains to be investigated [Current Zoology 59 (4: 564–568, 2013].
-
Archer, C Ruth; Hunt, John
2015-11-01
Aging evolved because the strength of natural selection declines over the lifetime of most organisms. Weak natural selection late in life allows the accumulation of deleterious mutations and may favor alleles that have positive effects on fitness early in life, but costly pleiotropic effects expressed later on. While this decline in natural selection is central to longstanding evolutionary explanations for aging, a role for sexual selection and sexual conflict in the evolution of lifespan and aging has only been identified recently. Testing how sexual selection and sexual conflict affect lifespan and aging is challenging as it requires quantifying male age-dependent reproductive success. This is difficult in the invertebrate model organisms traditionally used in aging research. Research using crickets (Orthoptera: Gryllidae), where reproductive investment can be easily measured in both sexes, has offered exciting and novel insights into how sexual selection and sexual conflict affect the evolution of aging, both in the laboratory and in the wild. Here we discuss how sexual selection and sexual conflict can be integrated alongside evolutionary and mechanistic theories of aging using crickets as a model. We then highlight the potential for research using crickets to further advance our understanding of lifespan and aging. Copyright © 2015 Elsevier Inc. All rights reserved.
-
Sexual dimorphism and directional sexual selection on aposematic signals in a poison frog
Maan, Martine E.; Cummings, Molly E.
2009-01-01
It is commonly assumed that natural selection imposed by predators is the prevailing force driving the evolution of aposematic traits. Here, we demonstrate that aposematic signals are shaped by sexual selection as well. We evaluated sexual selection for coloration brightness in populations of the
-
Sexual Selection of Protamine 1 in Mammals.
Lüke, Lena; Tourmente, Maximiliano; Roldan, Eduardo R S
2016-01-01
Protamines have a crucial role in male fertility. They are involved in sperm chromatin packaging and influence the shape of the sperm head and, hence, are important for sperm performance. Protamine structure is basic with numerous arginine-rich DNA-binding domains. Postcopulatory sexual selection is thought to play an important role in protamine sequence evolution and expression. Here, we analyze patterns of evolution and sexual selection (in the form of sperm competition) acting on protamine 1 gene sequence in 237 mammalian species. We assessed common patterns as well as differences between the major mammalian subclasses (Eutheria, Metatheria) and clades. We found that a high arginine content in protamine 1 associates with a lower sperm head width, which may have an impact on sperm swimming velocity. Increase in arginine content in protamine 1 across mammals appears to take place in a way consistent with sexual selection. In metatherians, increase in sequence length correlates with sexual selection. Differences in selective pressures on sequences and codon sites were observed between mammalian clades. Our study revealed a complex evolutionary pattern of protamine 1, with different selective constraints, and effects of sexual selection, between mammalian groups. In contrast, the effect of arginine content on head shape, and the possible involvement of sperm competition, was identified across all mammals. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
-
Homage to Bateman: sex roles predict sex differences in sexual selection.
Fritzsche, Karoline; Arnqvis, Göran
2013-07-01
Classic sex role theory predicts that sexual selection should be stronger in males in taxa showing conventional sex roles and stronger in females in role reversed mating systems. To test this very central prediction and to assess the utility of different measures of sexual selection, we estimated sexual selection in both sexes in four seed beetle species with divergent sex roles using a novel experimental design. We found that sexual selection was sizeable in females and the strength of sexual selection was similar in females and males in role-reversed species. Sexual selection was overall significantly stronger in males than in females and residual selection formed a substantial component of net selection in both sexes. Furthermore, sexual selection in females was stronger in role-reversed species compared to species with conventional sex roles. Variance-based measures of sexual selection (the Bateman gradient and selection opportunities) were better predictors of sexual dimorphism in reproductive behavior and morphology across species compared to trait-based measures (selection differentials). Our results highlight the importance of using assays that incorporate components of fitness manifested after mating. We suggest that the Bateman gradient is generally the most informative measure of the strength of sexual selection in comparisons across sexes and/or species. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.
-
Directory of Open Access Journals (Sweden)
Francisco Garcia-Gonzalez
2011-01-01
Full Text Available Whether species exhibit significant heritable variation in fitness is central for sexual selection. According to good genes models there must be genetic variation in males leading to variation in offspring fitness if females are to obtain genetic benefits from exercising mate preferences, or by mating multiply. However, sexual selection based on genetic benefits is controversial, and there is limited unambiguous support for the notion that choosy or polyandrous females can increase the chances of producing offspring with high viability. Here we examine the levels of additive genetic variance in two fitness components in the dung beetle Onthophagus taurus. We found significant sire effects on egg-to-adult viability and on son, but not daughter, survival to sexual maturity, as well as moderate coefficients of additive variance in these traits. Moreover, we do not find evidence for sexual antagonism influencing genetic variation for fitness. Our results are consistent with good genes sexual selection, and suggest that both pre- and postcopulatory mate choice, and male competition could provide indirect benefits to females.
-
Sexual and Natural Selection Both Influence Male Genital Evolution
House, Clarissa M.; Lewis, Zenobia; Hodgson, Dave J.; Wedell, Nina; Sharma, Manmohan D.; Hunt, John; Hosken, David J.
2013-01-01
Rapid and divergent evolution of male genital morphology is a conspicuous and general pattern across internally fertilizing animals. Rapid genital evolution is thought to be the result of sexual selection, and the role of natural selection in genital evolution remains controversial. However, natural and sexual selection are believed to act antagonistically on male genital form. We conducted an experimental evolution study to investigate the combined effects of natural and sexual selection on ...
-
Parental selection of children's sexual orientation.
Greenberg, A S; Bailey, J M
2001-08-01
As we learn more about the causes of sexual orientation, the likelihood increases that parents will one day be able to select the orientation of their children. This possibility (at least that of selecting for heterosexuality) has generated a great deal of concern among supporters of homosexual rights, with such selection being widely condemned as harmful and morally repugnant. Notwithstanding this widespread condemnation, and even assuming, as we do, that homosexuality is entirely acceptable morally, allowing parents, by means morally unproblematic in themselves, to select for heterosexuality would be morally acceptable. This is because allowing parents to select their children's sexual orientation would further parent's freedom to raise the sort of children they wish to raise and because selection for heterosexuality may benefit parents and children and is unlikely to cause significant harm.
-
Sexual selection predicts species richness across the animal kingdom.
Janicke, Tim; Ritchie, Michael G; Morrow, Edward H; Marie-Orleach, Lucas
2018-05-16
Our improving knowledge of the animal tree of life consistently demonstrates that some taxa diversify more rapidly than others, but what contributes to this variation remains poorly understood. An influential hypothesis proposes that selection arising from competition for mating partners plays a key role in promoting speciation. However, empirical evidence showing a link between proxies of this sexual selection and species richness is equivocal. Here, we collected standardized metrics of sexual selection for a broad range of animal taxa, and found that taxonomic families characterized by stronger sexual selection on males show relatively higher species richness. Thus, our data support the hypothesis that sexual selection elevates species richness. This could occur either by promoting speciation and/or by protecting species against extinction. © 2018 The Author(s).
-
Sexual selection in marine plankton
DEFF Research Database (Denmark)
Sichlau, Mie Hylstofte
Copepods are among the most abundant metazoans on the planet and play an important role in the marine food web. Many aspects of their ecology have consequently been studied, including details of their reproductive biology and mating behaviour. Sexual selection, the part of evolution which selects...
-
Darwin's explanation of races by means of sexual selection.
Millstein, Roberta L
2012-09-01
In Darwin's Sacred Cause, Adrian Desmond and James Moore contend that "Darwin would put his utmost into sexual selection because the subject intrigued him, no doubt, but also for a deeper reason: the theory vindicated his lifelong commitment to human brotherhood" (2009: p. 360). Without questioning Desmond and Moore's evidence, I will raise some puzzles for their view. I will show that attention to the structure of Darwin's arguments in the Descent of Man shows that they are far from straightforward. As Desmond and Moore note, Darwin seems to have intended sexual selection in non-human animals to serve as evidence for sexual selection in humans. However, Darwin's account of sexual selection in humans was different from the canonical cases that Darwin described at great length. If explaining the origin of human races was the main reason for introducing sexual selection, and if sexual selection was a key piece of Darwin's anti-slavery arguments, then it is puzzling why Darwin would have spent so much time discussing cases that did not really support his argument for the origin of human races, and it is also puzzling that his argument for the origin of human races would be so (atypically) poor. Copyright © 2012 Elsevier Ltd. All rights reserved.
-
Positive allometry and the prehistory of sexual selection.
Tomkins, Joseph L; LeBas, Natasha R; Witton, Mark P; Martill, David M; Humphries, Stuart
2010-08-01
The function of the exaggerated structures that adorn many fossil vertebrates remains largely unresolved. One recurrent hypothesis is that these elaborated traits had a role in thermoregulation. This orthodoxy persists despite the observation that traits exaggerated to the point of impracticality in extant organisms are almost invariably sexually selected. We use allometric scaling to investigate the role of sexual selection and thermoregulation in the evolution of exaggerated traits of the crested pterosaur Pteranodon longiceps and the sail-backed eupelycosaurs Dimetrodon and Edaphosaurus. The extraordinarily steep positive allometry of the head crest of Pteranodon rules out all of the current hypotheses for this trait's main function other than sexual signaling. We also find interspecific patterns of allometry and sexual dimorphism in the sails of Dimetrodon and patterns of elaboration in Edaphosaurus consistent with a sexually selected function. Furthermore, small ancestral, sail-backed pelycosaurs would have been too small to need adaptations to thermoregulation. Our results question the popular view that the elaborated structures of these fossil species evolved as thermoregulatory organs and provide evidence in support of the hypothesis that Pteranodon crests and eupelycosaur sails are among the earliest and most extreme examples of elaborate sexual signals in the evolution of terrestrial vertebrates.
-
Lessells, C.M.
2012-01-01
Parental care includes a wide variety of traits that enhance offspring development and survival. It is taxonomically widespread and is central to the maintenance of biodiversity through its close association with other phenomena such as sexual selection, life-history evolution, sex allocation,
-
Mate choice and sexual selection: what have we learned since Darwin?
Jones, Adam G; Ratterman, Nicholas L
2009-06-16
Charles Darwin laid the foundation for all modern work on sexual selection in his seminal book The Descent of Man, and Selection in Relation to Sex. In this work, Darwin fleshed out the mechanism of sexual selection, a hypothesis that he had proposed in The Origin of Species. He went well beyond a simple description of the phenomenon by providing extensive evidence and considering the far-reaching implications of the idea. Here we consider the contributions of Darwin to sexual selection with a particular eye on how far we have progressed in the last 150 years. We focus on 2 key questions in sexual selection. First, why does mate choice evolve at all? And second, what factors determine the strength of mate choice (or intensity of sexual selection) in each sex? Darwin provided partial answers to these questions, and the progress that has been made on both of these topics since his time should be seen as one of the great triumphs of modern evolutionary biology. However, a review of the literature shows that key aspects of sexual selection are still plagued by confusion and disagreement. Many of these areas are complex and will require new theory and empirical data for complete resolution. Overall, Darwin's contributions are still surprisingly relevant to the modern study of sexual selection, so students of evolutionary biology would be well advised to revisit his works. Although we have made significant progress in some areas of sexual selection research, we still have much to accomplish.
-
Sexual selection targets cetacean pelvic bones
Dines, J. P.; Otárola-Castillo, E.; Ralph, P.; Alas, J.; Daley, T.; Smith, A. D.; Dean, M. D.
2014-01-01
Male genitalia evolve rapidly, probably as a result of sexual selection. Whether this pattern extends to the internal infrastructure that influences genital movements remains unknown. Cetaceans (whales and dolphins) offer a unique opportunity to test this hypothesis: since evolving from land-dwelling ancestors, they lost external hind limbs and evolved a highly reduced pelvis which seems to serve no other function except to anchor muscles that maneuver the penis. Here we create a novel morphometric pipeline to analyze the size and shape evolution of pelvic bones from 130 individuals (29 species) in the context of inferred mating system. We present two main findings: 1) males from species with relatively intense sexual selection (inferred by relative testes size) have evolved relatively large penises and pelvic bones compared to their body size, and 2) pelvic bone shape diverges more quickly in species pairs that have diverged in inferred mating system. Neither pattern was observed in the anterior-most pair of vertebral ribs, which served as a negative control. This study provides evidence that sexual selection can affect internal anatomy that controls male genitalia. These important functions may explain why cetacean pelvic bones have not been lost through evolutionary time. PMID:25186496
-
Female Remating, Sperm Competition and Sexual Selection in Drosophila
Singh, Dr. Shree Ram; Singh, Dr. B N; Hoenigsberg, Dr. H F
2002-01-01
Female remating is the fundamental to evolutionary biology as it determines the pattern of sexual selection and sexual conflict. Remating in females is an important component of Drosophila mating systems because it is associated with pattern of sperm usage and sexual selection. Remating is common in females of many species of Drosophila in both natural and laboratory populations. It is reported in many insect species and vertebrates also. Female remating is prerequisite for the ...
-
[Sexual offences--selected cases].
Łabecka, Marzena; Jarzabek-Bielecka, Grazyna; Lorkiewicz-Muszyńska, Dorota
2013-04-01
Expert testimony on violence victims also includes victims of sexual assault. The role of an expert is to classify the injuries by their severity as defined in art. 157 156 or 217 of the Criminal Code pertaining to crimes against health and life. Also, the role of an expert opinion is to determine whether the injuries identified during the exam occurred at the time and under the circumstances stated in medical history. The examination of sexual assault victims is conducted by two experts: a gynecologist and a forensic physician. Most examinations are performed at different times and various medical centers. The conclusions are presented in an official report. Regardless of victim age, all sexual crimes are investigated ex officio by the Police Department and the Prosecutor's Office. Further legal classification of criminal offenses is the task of an appropriate legal body and the offenses are codified in accordance with the provisions of chapter XXV of the Criminal Code, articles 197 - 205. In controversial cases, i.e. when two different expert opinions appear on the same case, or if, according to the law enforcement, a medical opinion is insufficient for some reason, an appropriate expert or team of experts is appointed to resolve the problem. To present selected cases of sexual violence victims treated at the Department of Gynecology and assessed at the Department of Forensic Medicine with reference to the challenges regarding qualification of the sustained injuries and clinical diagnoses. Research material included selected forensic opinions developed for law enforcement offices that involved victims of sexual violence. The expert opinions were prepared either on the basis of submitted evidence, or both, submitted evidence and examination of the victim at the Department of Forensic Medicine. Moreover the article presents a case of a patient examined and treated at the Department of Gynecology in Poznan. Based on the selected cases, the authors conclude that a
-
Sexual selection and allometry: a critical reappraisal of the evidence and ideas.
Bonduriansky, Russell
2007-04-01
One of the most pervasive ideas in the sexual selection literature is the belief that sexually selected traits almost universally exhibit positive static allometries (i.e., within a sample of conspecific adults, larger individuals have disproportionally larger traits). In this review, I show that this idea is contradicted by empirical evidence and theory. Although positive allometry is a typical attribute of some sexual traits in certain groups, the preponderance of positively allometric sexual traits in the empirical literature apparently results from a sampling bias reflecting a fascination with unusually exaggerated (bizarre) traits. I review empirical examples from a broad range of taxa illustrating the diversity of allometric patterns exhibited by signal, weapon, clasping and genital traits, as well as nonsexual traits. This evidence suggests that positive allometry may be the exception rather than the rule in sexual traits, that directional sexual selection does not necessarily lead to the evolution of positive allometry and, conversely, that positive allometry is not necessarily a consequence of sexual selection, and that many sexual traits exhibit sex differences in allometric intercept rather than slope. Such diversity in the allometries of secondary sexual traits is to be expected, given that optimal allometry should reflect resource allocation trade-offs, and patterns of sexual and viability selection on both trait size and body size. An unbiased empirical assessment of the relation between sexual selection and allometry is an essential step towards an understanding of this diversity.
-
Positive allometry and the prehistory of sexual selection
Tomkins, Joseph L.; LeBas, Natasha R.; Witton, Mark P.; Martill, David M.; Humphries, Stuart
2010-01-01
The function of the exaggerated structures that adorn many fossil vertebrates remains largely unresolved. One recurrent hypothesis is that these elaborated traits had a role in thermoregulation. This orthodoxy persists despite the observation that traits exaggerated to the point of impracticality in extant organisms are almost invariably sexually selected. We use allometric scaling to investigate the role of sexual selection and thermoregulation in the evolution of exaggerated traits of the c...
-
Sexual selection, redundancy and survival of the most beautiful
Indian Academy of Sciences (India)
A model is described of a highly redundant complex organism that has overlapping banks of genes such that each vital function is specified by several different genetic systems. This generates a synergistic profile linking probability of survival to the number of deleterious mutations in the genome. Computer models show ...
-
The role of ecology in speciation by sexual selection: a systematic empirical review.
Scordato, Elizabeth S C; Symes, Laurel B; Mendelson, Tamra C; Safran, Rebecca J
2014-01-01
Theoretical and empirical research indicates that sexual selection interacts with the ecological context in which mate choice occurs, suggesting that sexual and natural selection act together during the evolution of premating reproductive isolation. However, the relative importance of natural and sexual selection to speciation remains poorly understood. Here, we applied a recent conceptual framework for examining interactions between mate choice divergence and ecological context to a review of the empirical literature on speciation by sexual selection. This framework defines two types of interactions between mate choice and ecology: internal interactions, wherein natural and sexual selection jointly influence divergence in sexual signal traits and preferences, and external interactions, wherein sexual selection alone acts on traits and preferences but ecological context shapes the transmission efficacy of sexual signals. The objectives of this synthesis were 3-fold: to summarize the traits, ecological factors, taxa, and geographic contexts involved in studies of mate choice divergence; to analyze patterns of association between these variables; and to identify the most common types of interactions between mate choice and ecological factors. Our analysis revealed that certain traits are consistently associated with certain ecological factors. Moreover, among studies that examined a divergent sexually selected trait and an ecological factor, internal interactions were more common than external interactions. Trait-preference associations may thus frequently be subject to both sexual and natural selection in cases of divergent mate choice. Our results highlight the importance of interactions between sexual selection and ecology in mate choice divergence and suggest areas for future research. © The American Genetic Association. 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
-
Sexual selection and magic traits in speciation with gene flow
Directory of Open Access Journals (Sweden)
Maria R. SERVEDIO, Michael KOPP
2012-06-01
Full Text Available The extent to which sexual selection is involved in speciation with gene flow remains an open question and the subject of much research. Here, we propose that some insight can be gained from considering the concept of magic traits (i.e., traits involved in both reproductive isolation and ecological divergence. Both magic traits and other, “non-magic”, traits can contribute to speciation via a number of specific mechanisms. We argue that many of these mechanisms are likely to differ widely in the extent to which they involve sexual selection. Furthermore, in some cases where sexual selection is present, it may be prone to inhibit rather than drive speciation. Finally, there are a priori reasons to believe that certain categories of traits are much more effective than others in driving speciation. The combination of these points suggests a classification of traits that may shed light on the broader role of sexual selection in speciation with gene flow. In particular, we suggest that sexual selection can act as a driver of speciation in some scenarios, but may play a negligible role in potentially common categories of magic traits, and may be likely to inhibit speciation in common categories of non-magic traits [Current Zoology 58 (3: 507–513, 2012].
-
Survival, growth and sexual maturation in Atlantic salmon exposed to infectious pancreatic necrosis
DEFF Research Database (Denmark)
Lillehammer, Marie; Ødegård, Jørgen; Madsen, Per
2013-01-01
tested on data consisting of 10 972 fish that died and 3959 survivors with recorded growth data. The most complex models (4 and 5) were multivariate normal-binary mixture models including growth, sexual maturity and field survival traits. Growth rate and liability of sexual maturation were treated as two...... identification of runts. Mixture models are commonly used to identify the underlying structures in such data, and the aim of this study was to develop Bayesian mixture models for the genetic analysis of health status (runt/healthy) of surviving fish from an IPN outbreak. Methods Five statistical models were......-component normal mixtures, assuming phenotypes originated from two potentially overlapping distributions, (runt/normal). Runt status was an unobserved binary trait. These models were compared to mixture models with fewer traits (Models 2 and 3) and a classical linear animal model for growth (Model 1). Results...
-
The geography of sex-specific selection, local adaptation, and sexual dimorphism.
Connallon, Tim
2015-09-01
Local adaptation and sexual dimorphism are iconic evolutionary scenarios of intraspecific adaptive differentiation in the face of gene flow. Although theory has traditionally considered local adaptation and sexual dimorphism as conceptually distinct processes, emerging data suggest that they often act concurrently during evolutionary diversification. Here, I merge theories of local adaptation in space and sex-specific adaptation over time, and show that their confluence yields several new predictions about the roles of context-specific selection, migration, and genetic correlations, in adaptive diversification. I specifically revisit two influential predictions from classical studies of clinal adaptation and sexual dimorphism: (1) that local adaptation should decrease with distance from the species' range center and (2) that opposing directional selection between the sexes (sexual antagonism) should inevitably accompany the evolution of sexual dimorphism. I show that both predictions can break down under clinally varying selection. First, the geography of local adaptation can be sexually dimorphic, with locations of relatively high local adaptation differing profoundly between the sexes. Second, the intensity of sexual antagonism varies across the species' range, with subpopulations near the range center representing hotspots for antagonistic selection. The results highlight the context-dependent roles of migration versus sexual conflict as primary constraints to adaptive diversification. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.
-
Trajković, Jelena; Miličić, Dragana; Savić, Tatjana; Pavković-Lučić, Sofija
2017-07-01
Evolution of reproductive isolation may be a consequence of a variety of signals used in courtship and mate preferences. Pheromones play an important role in both sexual selection and sexual isolation. The abundance of pheromones in Drosophila melanogaster may depend on different environmental factors, including diet. The aim of this study was to ascertain to which degree principal pheromones affect sexual selection in D. melanogaster. We used D. melanogaster strains reared for 14 years on four substrates: standard cornmeal substrate and those containing tomato, banana and carrot. We have previously determined that long-term maintaining of these dietary strains resulted in differences in their cuticular hydrocarbons profile (CHs). In this work, we have tested the level of sexual selection and sexual isolation between aforementioned strains. We found that the high levels of cis-vaccenyl acetate, 7-pentacosene and 7,11-nonacosadiene in the strain reared on a substrate containing carrot affected the individual attractiveness and influenced sexual isolation between flies of this strain and flies reared on a substrate containing banana. Based on these results, long-term different diets, may contribute, to sexual behaviour of D. melanogaster via the effects of principal pheromones. Copyright © 2017 Elsevier B.V. All rights reserved.
-
Sexual selection halts the relaxation of protamine 2 among rodents.
Directory of Open Access Journals (Sweden)
Lena Lüke
Full Text Available Sexual selection has been proposed as the driving force promoting the rapid evolutionary changes observed in some reproductive genes including protamines. We test this hypothesis in a group of rodents which show marked differences in the intensity of sexual selection. Levels of sperm competition were not associated with the evolutionary rates of protamine 1 but, contrary to expectations, were negatively related to the evolutionary rate of cleaved- and mature-protamine 2. Since both domains were found to be under relaxation, our findings reveal an unforeseen role of sexual selection: to halt the degree of degeneration that proteins within families may experience due to functional redundancy. The degree of relaxation of protamine 2 in this group of rodents is such that in some species it has become dysfunctional and it is not expressed in mature spermatozoa. In contrast, protamine 1 is functionally conserved but shows directed positive selection on specific sites which are functionally relevant such as DNA-anchoring domains and phosphorylation sites. We conclude that in rodents protamine 2 is under relaxation and that sexual selection removes deleterious mutations among species with high levels of sperm competition to maintain the protein functional and the spermatozoa competitive.
-
Do extra-group fertilizations increase the potential for sexual selection in male mammals?
Isvaran, Kavita; Sankaran, Sumithra
2017-10-01
Fertilizations by males outside the social breeding group (extra-group paternity, EGP) are widespread in birds and mammals. EGP is generally proposed to increase male reproductive skew and thereby increase the potential for sexual selection, but the generality of this relationship is unclear. We extracted data from 27 mammals in seven orders and used phylogenetic comparative methods to investigate the influence of EGP and social mating system on measures of inequality in male fertilization success, which are indices of the potential for sexual selection. We find that EGP and social mating system can predict the potential for sexual selection in mammalian populations, but only when considered jointly and not individually. EGP appears to increase the potential for sexual selection but only when the degree of social polygyny is relatively low. When social polygyny is high, EGP appears to result in a more uniform distribution of reproduction and a decrease in the potential for sexual selection. A possible explanation to be investigated is that the phenotype of extra-group fathers differs systematically across social mating systems. Our findings have implications for the use of EGP and social mating system as indices of sexual selection in comparative analyses of trait evolution under sexual selection. © 2017 The Author(s).
-
Safran, Rebecca J; Scordato, Elizabeth S C; Symes, Laurel B; Rodríguez, Rafael L; Mendelson, Tamra C
2013-11-01
Speciation by divergent natural selection is well supported. However, the role of sexual selection in speciation is less well understood due to disagreement about whether sexual selection is a mechanism of evolution separate from natural selection, as well as confusion about various models and tests of sexual selection. Here, we outline how sexual selection and natural selection are different mechanisms of evolutionary change, and suggest that this distinction is critical when analyzing the role of sexual selection in speciation. Furthermore, we clarify models of sexual selection with respect to their interaction with ecology and natural selection. In doing so, we outline a research agenda for testing hypotheses about the relative significance of divergent sexual and natural selection in the evolution of reproductive isolation. Copyright © 2013 Elsevier Ltd. All rights reserved.
-
Directory of Open Access Journals (Sweden)
Kim Aleksander Tallaksen Halvorsen
2015-12-01
Full Text Available Corkwing wrasse (Symphodus melops is a temperate wrasse displaying both sex and male dimorphism and is targeted in a size selective commercial fishery which has increased dramatically since 2008. Wrasses are supplied alive to salmon farms as cleaner fish to combat infestations of Salmon lice. In previous studies, growth and maturation has been found to differ among male morphs and sexes and these groups might therefore be targeted unevenly by the size selective fishery. In the present study, we address this by comparing size regulations and fishing practice with data on sex specific growth and maturation from Western and Southern Norway, two regions varying in density and life histories. Two years of field data on density and length measures was used together with a subsample of otoliths to determine sex specific growth patterns. In the region with high density, nesting males were found to grow faster and mature later than sneaker males and females. Here, most nesting males will reach the minimum size as juveniles, one and two years before females and sneakers respectively. In contrast, sexual dimorphism was much less pronounced in the low density region, and relaxed male-male competition over nesting sites seems a likely explanation for this pattern. Intensive harvesting with selective removal of the larger nesting males could potentially lead to short term effect such as sperm limitation and reduced offspring survival and thus affect the productivity of juveniles. In addition, the current fishing regime may select for reduced growth rates and earlier maturation and oppose sexual selection.
-
Sexual selection affects local extinction and turnover in bird communities
Doherty, P.F.; Sorci, G.; Royle, J. Andrew; Hines, J.E.; Nichols, J.D.; Boulinier, T.
2003-01-01
Predicting extinction risks has become a central goal for conservation and evolutionary biologists interested in population and community dynamics. Several factors have been put forward to explain risks of extinction, including ecological and life history characteristics of individuals. For instance, factors that affect the balance between natality and mortality can have profound effects on population persistence. Sexual selection has been identified as one such factor. Populations under strong sexual selection experience a number of costs ranging from increased predation and parasitism to enhanced sensitivity to environmental and demographic stochasticity. These findings have led to the prediction that local extinction rates should be higher for species/populations with intense sexual selection. We tested this prediction by analyzing the dynamics of natural bird communities at a continental scale over a period of 21 years (1975-1996), using relevant statistical tools. In agreement with the theoretical prediction, we found that sexual selection increased risks of local extinction (dichromatic birds had on average a 23% higher local extinction rate than monochromatic species). However, despite higher local extinction probabilities, the number of dichromatic species did not decrease over the period considered in this study. This pattern was caused by higher local turnover rates of dichromatic species, resulting in relatively stable communities for both groups of species. Our results suggest that these communities function as metacommunities, with frequent local extinctions followed by colonization. Anthropogenic factors impeding dispersal might therefore have a significant impact on the global persistence of sexually selected species.
-
Sexual Selection and the differences between the sexes in Mandrills (Mandrillus sphinx).
Setchell, Joanna M
2016-01-01
Sexual selection has become a major focus in evolutionary and behavioral ecology. It is also a popular research topic in primatology. I use studies of mandrills (Mandrillus sphinx), a classic example of extravagant armaments and ornaments in animals, to exemplify how a long-term, multidisciplinary approach that integrates field observations with laboratory methods can contribute to on-going theoretical debates in the field of sexual selection. I begin with a brief summary of the main concepts of sexual selection theory and the differences between the sexes. I then introduce mandrills and the study population and review mandrill life history, the ontogeny of sex differences, and maternal effects. Next, I focus on male-male competition and female choice, followed by the less well-studied questions of female-female competition and male choice. This review shows how different reproductive priorities lead to very different life histories and divergent adaptations in males and females. It demonstrates how broadening traditional perspectives on sexual selection beyond the ostentatious results of intense sexual selection on males leads to an understanding of more subtle and cryptic forms of competition and choice in both sexes and opens many productive avenues in the study of primate reproductive strategies. These include the potential for studies of postcopulatory selection, female intrasexual competition, and male choice. These studies of mandrills provide comparison and, I hope, inspiration for studies of both other polygynandrous species and species with mating systems less traditionally associated with sexual selection. © 2016 Wiley Periodicals, Inc.
-
Sexual selection by male choice in monogamous and polygynous human populations.
Ihara, Y; Aoki, K
1999-02-01
The theoretical possibility of coevolution of a viability-reducing female physical trait and a male mating preference for that trait by Fisherian sexual selection in monogamous and polygynous populations is demonstrated using two-locus haploid models. It is assumed that there is dichotomous variation in male resources, resource-rich males have a wider choice among females than resource-poor males, and a female has greater reproductive success when mated with a resource-rich male than a resource-poor one. Under these assumptions, we find that sexual selection operates effectively when female reproductive success is strongly dependent on male resource, the proportion of females that mate with resource-rich males is neither small nor large, the degree of polygyny is low, and resources are inherited from father to son. We suggest that some human female physical traits may have evolved by sexual selection through male choice. The evolution of skin color by sexual selection is discussed as an example. Copyright 1999 Academic Press.
-
Postcopulatory sexual selection is associated with reduced variation in sperm morphology.
Directory of Open Access Journals (Sweden)
Sara Calhim
2007-05-01
Full Text Available The evolutionary role of postcopulatory sexual selection in shaping male reproductive traits, including sperm morphology, is well documented in several taxa. However, previous studies have focused almost exclusively on the influence of sperm competition on variation among species. In this study we tested the hypothesis that intraspecific variation in sperm morphology is driven by the level of postcopulatory sexual selection in passerine birds.Using two proxy measures of sperm competition level, (i relative testes size and (ii extrapair paternity level, we found strong evidence that intermale variation in sperm morphology is negatively associated with the degree of postcopulatory sexual selection, independently of phylogeny.Our results show that the role of postcopulatory sexual selection in the evolution of sperm morphology extends to an intraspecific level, reducing the variation towards what might be a species-specific 'optimum' sperm phenotype. This finding suggests that while postcopulatory selection is generally directional (e.g., favouring longer sperm across avian species, it also acts as a stabilising evolutionary force within species under intense selection, resulting in reduced variation in sperm morphology traits. We discuss some potential evolutionary mechanisms for this pattern.
-
Testing for a genetic response to sexual selection in a wild Drosophila population.
Gosden, T P; Thomson, J R; Blows, M W; Schaul, A; Chenoweth, S F
2016-06-01
In accordance with the consensus that sexual selection is responsible for the rapid evolution of display traits on macroevolutionary scales, microevolutionary studies suggest sexual selection is a widespread and often strong form of directional selection in nature. However, empirical evidence for the contemporary evolution of sexually selected traits via sexual rather than natural selection remains weak. In this study, we used a novel application of quantitative genetic breeding designs to test for a genetic response to sexual selection on eight chemical display traits from a field population of the fly, Drosophila serrata. Using our quantitative genetic approach, we were able to detect a genetically based difference in means between groups of males descended from fathers who had either successfully sired offspring or were randomly collected from the same wild population for one of these display traits, the diene (Z,Z)-5,9-C27 : 2 . Our experimental results, in combination with previous laboratory studies on this system, suggest that both natural and sexual selection may be influencing the evolutionary trajectories of these traits in nature, limiting the capacity for a contemporary evolutionary response. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.
-
Allen, Scott L; McGuigan, Katrina; Connallon, Tim; Blows, Mark W; Chenoweth, Stephen F
2017-10-01
A proposed benefit to sexual selection is that it promotes purging of deleterious mutations from populations. For this benefit to be realized, sexual selection, which is usually stronger on males, must purge mutations deleterious to both sexes. Here, we experimentally test the hypothesis that sexual selection on males purges deleterious mutations that affect both male and female fitness. We measured male and female fitness in two panels of spontaneous mutation-accumulation lines of the fly, Drosophila serrata, each established from a common ancestor. One panel of mutation accumulation lines limited both natural and sexual selection (LS lines), whereas the other panel limited natural selection, but allowed sexual selection to operate (SS lines). Although mutation accumulation caused a significant reduction in male and female fitness in both the LS and SS lines, sexual selection had no detectable effect on the extent of the fitness reduction. Similarly, despite evidence of mutational variance for fitness in males and females of both treatments, sexual selection had no significant impact on the amount of mutational genetic variance for fitness. However, sexual selection did reshape the between-sex correlation for fitness: significantly strengthening it in the SS lines. After 25 generations, the between-sex correlation for fitness was positive but considerably less than one in the LS lines, suggesting that, although most mutations had sexually concordant fitness effects, sex-limited, and/or sex-biased mutations contributed substantially to the mutational variance. In the SS lines this correlation was strong and could not be distinguished from unity. Individual-based simulations that mimick the experimental setup reveal two conditions that may drive our results: (1) a modest-to-large fraction of mutations have sex-limited (or highly sex-biased) fitness effects, and (2) the average fitness effect of sex-limited mutations is larger than the average fitness effect of
-
Puniamoorthy, Nalini; Schäfer, Martin A; Blanckenhorn, Wolf U
2012-07-01
Sexual size dimorphism (SSD) varies widely across and within species. The differential equilibrium model of SSD explains dimorphism as the evolutionary outcome of consistent differences in natural and sexual selection between the sexes. Here, we comprehensively examine a unique cross-continental reversal in SSD in the dung fly, Sepsis punctum. Using common garden laboratory experiments, we establish that SSD is male-biased in Europe and female-biased in North America. When estimating sexual (pairing success) and fecundity selection (clutch size of female partner) on males under three operational sex ratios (OSRs), we find that the intensity of sexual selection is significantly stronger in European versus North American populations, increasing with male body size and OSR in the former only. Fecundity selection on female body size also increases strongly with egg number and weakly with egg volume, however, equally on both continents. Finally, viability selection on body size in terms of intrinsic (physiological) adult life span in the laboratory is overall nil and does not vary significantly across all seven populations. Although it is impossible to prove causality, our results confirm the differential equilibrium model of SSD in that differences in sexual selection intensity account for the reversal in SSD in European versus North American populations, presumably mediating the ongoing speciation process in S. punctum. © 2012 The Author(s).
-
Sexual Selection Revisited ? Towards a Gender-Neutral Theory and Practice
2007-01-01
Abstract In a recent issue of this journal, Vandermassen suggested that feminists should include sexual selection theory and evolutionary psychology in a unifying theory of human nature. In response, this article aims to offer some insight into the development of sexual selection theory, to caution against Vandermassen's unreserved assimilation and to promote the opposite ongoing integration ? an inclusion of gender perspectives into evolutionary biology. In society today, opinions...
-
Sexual Selection on male cuticular hydrocarbons via male-male competition and female choice.
Lane, S M; Dickinson, A W; Tregenza, T; House, C M
2016-07-01
Traditional views of sexual selection assumed that male-male competition and female mate choice work in harmony, selecting upon the same traits in the same direction. However, we now know that this is not always the case and that these two mechanisms often impose conflicting selection on male sexual traits. Cuticular hydrocarbons (CHCs) have been shown to be linked to both social dominance and male attractiveness in several insect species. However, although several studies have estimated the strength and form of sexual selection imposed on male CHCs by female mate choice, none have established whether these chemical traits are also subject to sexual selection via male-male competition. Using a multivariate selection analysis, we estimate and compare sexual selection exerted by male-male competition and female mate choice on male CHC composition in the broad-horned flour beetle Gnatocerus cornutus. We show that male-male competition exerts strong linear selection on both overall CHC abundance and body size in males, while female mate choice exerts a mixture of linear and nonlinear selection, targeting not just the overall amount of CHCs expressed but the relative abundance of specific hydrocarbons as well. We discuss the potential implications of this antagonistic selection with regard to male reproductive success. © 2016 The Authors. Journal of Evolutionary Biology published by John Wiley & Sons Ltd on behalf of European Society for Evolutionary Biology.
-
Sex in murky waters: algal-induced turbidity increases sexual selection in pipefish.
Sundin, Josefin; Aronsen, Tonje; Rosenqvist, Gunilla; Berglund, Anders
2017-01-01
Algal-induced turbidity has been shown to alter several important aspects of reproduction and sexual selection. However, while turbidity has been shown to negatively affect reproduction and sexually selected traits in some species, it may instead enhance reproductive success in others, implying that the impact of eutrophication is far more complex than originally believed. In this study, we aimed to provide more insight into these inconsistent findings. We used molecular tools to investigate the impact of algal turbidity on reproductive success and sexual selection on males in controlled laboratory experiments, allowing mate choice, mating competition, and mate encounter rates to affect reproduction. As study species, we used the broad-nosed pipefish, Syngnathus typhle , a species practicing male pregnancy and where we have previously shown that male mate choice is impaired by turbidity. Here, turbidity instead enhanced sexual selection on male size and mating success as well as reproductive success. Effects from mating competition and mate encounter rates may thus override effects from mate choice based on visual cues, producing an overall stronger sexual selection in turbid waters. Hence, seemingly inconsistent effects of turbidity on sexual selection may depend on which mechanisms of sexual selection that have been under study. Algal blooms are becoming increasingly more common due to eutrophication of freshwater and marine environments. The high density of algae lowers water transparency and reduces the possibility for fish and other aquatic animals to perform behaviors dependent on vision. We have previously shown that pipefish are unable to select the best partner in mate choice trials when water transparency was reduced. However, fish might use other senses than vision to compensate for the reduction in water transparency. In this study, we found that when fish were allowed to freely interact, thereby allowing competition between partners and direct contact
-
Natural and sexual selection against hybrid flycatchers
Svedin, Nina; Wiley, Chris; Veen, Thor; Gustafsson, Lars; Qvarnstrom, Anna
2008-01-01
While sexual selection is generally assumed to quickly cause or strengthen prezygotic barriers between sister species, its role in causing postzygotic isolation, through the unattractiveness of intermediate hybrids, is less often examined. Combining 24 years of pedigree data and recently developed
-
Can sexual selection drive female life histories? A comparative study on Galliform birds.
Kolm, N; Stein, R W; Mooers, A Ø; Verspoor, J J; Cunningham, E J A
2007-03-01
Sexual selection has been identified as a major evolutionary force shaping male life history traits but its impact on female life history evolution is less clear. Here we examine the impact of sexual selection on three key female traits (body size, egg size and clutch size) in Galliform birds. Using comparative independent contrast analyses and directional discrete analyses, based on published data and a new genera-level supertree phylogeny of Galliform birds, we investigated how sexual selection [quantified as sexual size dimorphism (SSD) and social mating system (MS)] affects these three important female traits. We found that female body mass was strongly and positively correlated with egg size but not with clutch size, and that clutch size decreased as egg size increased. We established that SSD was related to MS, and then used SSD as a proxy of the strength of sexual selection. We found both a positive relationship between SSD and female body mass and egg size and that increases in female body mass and egg size tend to occur following increases in SSD in this bird order. This pattern of female body mass increases lagging behind changes in SSD, established using our directional discrete analysis, suggests that female body mass increases as a response to increases in the level of sexual selection and not simply through a strong genetic relationship with male body mass. This suggests that sexual selection is linked to changes in female life history traits in Galliformes and we discuss how this link may shape patterns of life history variation among species.
-
Evolution of male and female genitalia following release from sexual selection.
Cayetano, Luis; Maklakov, Alexei A; Brooks, Robert C; Bonduriansky, Russell
2011-08-01
Despite the key functions of the genitalia in sexual interactions and fertilization, the role of sexual selection and conflict in shaping genital traits remains poorly understood. Seed beetle (Callosobruchus maculatus) males possess spines on the intromittent organ, and females possess a thickened reproductive tract wall that also bears spines. We investigated the role of sexual selection and conflict by imposing monogamous mating on eight replicate populations of this naturally polygamous insect, while maintaining eight other populations under polygamy. To establish whether responses to mating system manipulation were robust to ecological context, we simultaneously manipulated life-history selection (early/late reproduction). Over 18-21 generations, male genital spines evolved relatively reduced length in large males (i.e., shallower static allometry) in monogamous populations. Two nonintromittent male genital appendages also evolved in response to the interaction of mating system and ecology. In contrast, no detectable evolution occurred in female genitalia, consistent with the expectation of a delayed response in defensive traits. Our results support a sexually antagonistic role for the male genital spines, and demonstrate the evolution of static allometry in response to variation in sexual selection opportunity. We argue that further advances in the study of genital coevolution will require a much more detailed understanding of the functions of male and female genital traits. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
-
No Evidence for Pre-Copulatory Sexual Selection on Sperm Length in a Passerine Bird
Lifjeld, Jan T.; Laskemoen, Terje; Kleven, Oddmund; Pedersen, A. Tiril M.; Lampe, Helene M.; Rudolfsen, Geir; Schmoll, Tim; Slagsvold, Tore
2012-01-01
There is growing evidence that post-copulatory sexual selection, mediated by sperm competition, influences the evolution of sperm phenotypes. Evidence for pre-copulatory sexual selection effects on sperm traits, on the other hand, is rather scarce. A recent paper on the pied flycatcher, Ficedula hypoleuca, reported phenotypic associations between sperm length and two sexually selected male traits, i.e. plumage colour and arrival date, thus invoking pre-copulatory sexual selection for longer sperm. We were unable to replicate these associations with a larger data set from the same and two additional study populations; sperm length was not significantly related to either male plumage colour or arrival date. Furthermore, there was no significant difference in sperm length between populations despite marked differences in male plumage colour. We also found some evidence against the previously held assumption of longer sperm being qualitatively superior; longer sperm swam at the same speed as shorter sperm, but were less able to maintain speed over time. We argue that both empirical evidence and theoretical considerations suggest that the evolution of sperm morphology is not primarily associated with pre-copulatory sexual selection on male secondary sexual traits in this or other passerine bird species. The relatively large between-male variation in sperm length in this species is probably due to relaxed post-copulatory sexual selection. PMID:22384277
-
No evidence for pre-copulatory sexual selection on sperm length in a passerine bird.
Directory of Open Access Journals (Sweden)
Jan T Lifjeld
Full Text Available There is growing evidence that post-copulatory sexual selection, mediated by sperm competition, influences the evolution of sperm phenotypes. Evidence for pre-copulatory sexual selection effects on sperm traits, on the other hand, is rather scarce. A recent paper on the pied flycatcher, Ficedula hypoleuca, reported phenotypic associations between sperm length and two sexually selected male traits, i.e. plumage colour and arrival date, thus invoking pre-copulatory sexual selection for longer sperm. We were unable to replicate these associations with a larger data set from the same and two additional study populations; sperm length was not significantly related to either male plumage colour or arrival date. Furthermore, there was no significant difference in sperm length between populations despite marked differences in male plumage colour. We also found some evidence against the previously held assumption of longer sperm being qualitatively superior; longer sperm swam at the same speed as shorter sperm, but were less able to maintain speed over time. We argue that both empirical evidence and theoretical considerations suggest that the evolution of sperm morphology is not primarily associated with pre-copulatory sexual selection on male secondary sexual traits in this or other passerine bird species. The relatively large between-male variation in sperm length in this species is probably due to relaxed post-copulatory sexual selection.
-
Benign meningiomas: primary treatment selection affects survival
International Nuclear Information System (INIS)
Condra, Kellie S.; Buatti, John M.; Mendenhall, William M.; Friedman, William A.; Marcus, Robert B.; Rhoton, Albert L.
1997-01-01
Purpose: To examine the effect of primary treatment selection on outcomes for benign intracranial meningiomas at the University of Florida. Methods and Materials: For 262 patients, the impact of age, Karnofsky performance status, pathologic features, tumor size, tumor location, and treatment modality on local control and cause-specific survival was analyzed (minimum potential follow-up, 2 years; median follow-up, 8.2 years). Extent of surgery was classified by Simpson grade. Treatment groups: surgery alone (n = 229), surgery and postoperative radiotherapy (RT) (n = 21), RT alone (n = 7), radiosurgery alone (n = 5). Survival analysis: Kaplan-Meier method with univariate and multivariate analysis. Results: At 15 years, local control was 76% after total excision (TE) and 87% after subtotal excision plus RT (SE+RT), both significantly better (p = 0.0001) than after SE alone (30%). Cause-specific survival at 15 years was reduced after treatment with SE alone (51%), compared with TE (88%) or SE+RT (86%) (p = 0.0003). Recurrence after primary treatment portended decreased survival, independent of initial treatment group or salvage treatment selection (p = 0.001). Atypical pathologic features predicted reduced 15-year local control (54 vs. 71%) and cause-specific survival rates (57 vs. 86%). Multivariate analysis for cause-specific survival revealed treatment group (SE vs. others; p = 0.0001), pathologic features (atypical vs. typical; p = 0.0056), and Karnofsky performance status (≥80 vs. <80; p = 0.0153) as significant variables. Conclusion: Benign meningiomas are well managed by TE or SE+RT. SE alone is inadequate therapy and adversely affects cause-specific survival. Atypical pathologic features predict a poorer outcome, suggesting possible benefit from more aggressive treatment. Because local recurrence portends lower survival rates, primary treatment choice is important
-
Student-Initiated Sexual Health Selective as a Curricular Tool
Directory of Open Access Journals (Sweden)
Katie Johnson, BS
2015-06-01
Conclusions: The 1-week SHS was successfully implemented through the teamwork of a medical student and faculty champion. It resulted in more accurate knowledge and more open attitudes toward sexual health among participating medical students. Potential benefits to undergraduate medical educators are reviewed. Johnson K, Rullo J, and Faubion S. Student-initiated sexual health selective as a curricular tool. Sex Med 2015;3:118–127.
-
Sexual selection studies: A NESCent catalyst meeting
Roughgarden, J.; Adkins-Regan, E.; Akcay, E.; Hinde, C.A.; Hoquet, T.; O'Connor, C.; Prokop, Z.M.; Prum, R.O.; Shafir, S.; Snow, S.S.; Taylor, D.; Cleve, Van J.; Weisberg, M.
2015-01-01
A catalyst meeting on sexual selection studies was held in July 2013 at the facilities of the National Evolutionary Synthesis Center (NESCent) in Durham, NC. This article by a subcommittee of the participants foregrounds some of the topics discussed at the meeting. Topics mentioned here include the
-
Stronger sexual selection in warmer waters: the case of a sex role reversed pipefish.
Directory of Open Access Journals (Sweden)
Nuno M Monteiro
Full Text Available In order to answer broader questions about sexual selection, one needs to measure selection on a wide array of phenotypic traits, simultaneously through space and time. Nevertheless, studies that simultaneously address temporal and spatial variation in reproduction are scarce. Here, we aimed to investigate the reproductive dynamics of a cold-water pipefish simultaneously through time (encompassing variation within each breeding cycle and as individuals grow and space (by contrasting populations experiencing distinct water temperature regimes in order to test hypothesized differences in sexual selection. Even though the sampled populations inhabited locations with very different water temperature regimes, they exhibited considerable similarities in reproductive parameters. The most striking was the existence of a well-defined substructure in reproductive activity, where larger individuals reproduce for longer periods, which seemed dependent on a high temperature threshold for breeding rather than on the low temperatures that vary heavily according to latitude. Furthermore, the perceived disparities among populations, such as size at first reproduction, female reproductive investment, or degree of sexual size dimorphism, seemed dependent on the interplay between seawater temperature and the operational sex ratio (OSR. Contrary to our expectations of an enhanced opportunity for sexual selection in the north, we found the opposite: higher female reproductive investment coupled with increased sexual size dimorphism in warmer waters, implying that a prolonged breeding season does not necessarily translate into reduced sexual selection pressure. In fact, if the limited sex has the ability to reproduce either continuously or recurrently during the entire breeding season, an increased opportunity for sexual selection might arise from the need to compete for available partners under strongly biased OSRs across protracted breeding seasons. A more general
-
Novel host plant leads to the loss of sexual dimorphism in a sexually selected male weapon.
Allen, Pablo E; Miller, Christine W
2017-08-16
In this time of massive global change, species are now frequently interacting with novel players. Greater insight into the impact of these novel interactions on traits linked to fitness is essential, because effects on these traits can hinder population existence or promote rapid adaptation. Sexually selected weapons and ornaments frequently influence fitness and often have heightened condition-dependence in response to nutrition. Condition-dependence in response to different ecological conditions, a form of developmental plasticity, may be responsible for much of the intraspecific variation in sexually selected ornaments and weapons in wild populations. Here we examined the consequences of developing on a novel plant for the expression of size and shape in the leaf-footed cactus bug Narnia femorata (Hemiptera: Coreidae). The males of this species possess enlarged, sexually dimorphic femurs on their hind legs. These legs are used as weapons in male-male contests. Females are typically larger in overall body size. Our study revealed that developing upon a novel host can lead to pronounced phenotypically plastic change in sexually dimorphic traits. Male hind femurs were greatly impacted by the novel diet to the extent that the sexual dimorphism in hind femurs was lost. Further, dimorphism in body size increased, as males became tiny adults while females better maintained their body size. These patterns underscore the complex effects that novel species interactions may have on sexual phenotypes. © 2017 The Author(s).
-
Postcopulatory sexual selection influences baculum evolution in primates and carnivores.
Brindle, Matilda; Opie, Christopher
2016-12-14
The extreme morphological variability of the baculum across mammals is thought to be the result of sexual selection (particularly, high levels of postcopulatory selection). However, the evolutionary trajectory of the mammalian baculum is little studied and evidence for the adaptive function of the baculum has so far been elusive. Here, we use Markov chain Monte Carlo methods implemented in a Bayesian phylogenetic framework to reconstruct baculum evolution across the mammalian class and investigate the rate of baculum length evolution within the primate order. We then test the effects of testes mass (postcopulatory sexual selection), polygamy, seasonal breeding and intromission duration on the baculum in primates and carnivores. The ancestral mammal did not have a baculum, but both ancestral primates and carnivores did. No relationship was found between testes mass and baculum length in either primates or carnivores. Intromission duration correlated with baculum presence over the course of primate evolution, and prolonged intromission predicts significantly longer bacula in extant primates and carnivores. Both polygamous and seasonal breeding systems predict significantly longer bacula in primates. These results suggest the baculum plays an important role in facilitating reproductive strategies in populations with high levels of postcopulatory sexual selection. © 2016 The Authors.
-
Nonsteroidal selective androgen receptor modulators enhance female sexual motivation.
Jones, Amanda; Hwang, Dong Jin; Duke, Charles B; He, Yali; Siddam, Anjaiah; Miller, Duane D; Dalton, James T
2010-08-01
Women experience a decline in estrogen and androgen levels after natural or surgically induced menopause, effects that are associated with a loss of sexual desire and bone mineral density. Studies in our laboratories have shown the beneficial effects of selective androgen receptor modulators (SARMs) in the treatment of osteoporosis and muscle wasting in animal models. A series of S-3-(phenoxy)-2-hydroxy-2-methyl-N-(4-cyano-3-trifluoromethyl-phenyl)-propionamide analogs was synthesized to evaluate the effects of B-ring substitutions on in vitro and in vivo pharmacologic activity, especially female sexual motivation. The androgen receptor (AR) relative binding affinities ranged from 0.1 to 26.5% (relative to dihydrotestosterone) and demonstrated a range of agonist activity at 100 nM. In vivo pharmacologic activity was first assessed by using male rats. Structural modifications to the B-ring significantly affected the selectivity of the SARMs, demonstrating that single-atom substitutions can dramatically and unexpectedly influence activity in androgenic (i.e., prostate) and anabolic (i.e., muscle) tissues. (S)-N-(4-cyano-3-trifluoromethyl-phenyl)-3-(3-fluoro,4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide (S-23) displayed full agonist activity in androgenic and anabolic tissues; however, the remaining SARMs were more prostate-sparing, selectively maintaining the size of the levator ani muscle in castrated rats. The partner-preference paradigm was used to evaluate the effects of SARMs on female sexual motivation. With the exception of two four-halo substituted analogs, the SARMs increased sexual motivation in ovariectomized rats, with potency and efficacy comparable with testosterone propionate. These results indicate that the AR is important in regulating female libido given the nonaromatizable nature of SARMs and it could be a superior alternative to steroidal testosterone preparations in the treatment of hypoactive sexual desire disorder.
-
Kin selection versus sexual selection: why the ends do not meet
DEFF Research Database (Denmark)
Boomsma, Jacobus J
2007-01-01
non-social and cooperative breeding. Sexually selected traits in eusocial lineages are therefore peculiar, and their evolution constrained. Indirect (inclusive) fitness benefits in cooperatively breeding vertebrates appear to be negatively correlated with promiscuity, corroborating that kin selection......I redevelop the hypothesis that lifetime monogamy is a fundamental condition for the evolution of eusocial lineages with permanent non-reproductive castes, and that later elaborations--such as multiply-mated queens and multi-queen colonies--arose without the re-mating promiscuity that characterizes...
-
Directory of Open Access Journals (Sweden)
Mirre J P Simons
Full Text Available Sexual traits can serve as honest indicators of phenotypic quality when they are costly. Brightly coloured yellow to red traits, which are pigmented by carotenoids, are relatively common in birds, and feature in sexual selection. Carotenoids have been linked to immune and antioxidant function, and the trade-off between ornamentation and these physiological functions provides a potential mechanism rendering carotenoid based signals costly. Mutual ornamentation is also common in birds and can be maintained by mutual mate choice for this ornament or by a correlated response in one sex to selection on the other sex. When selection pressures differ between the sexes this can cause intralocus sexual conflict. Sexually antagonistic selection pressures have been demonstrated for few sexual traits, and for carotenoid-dependent traits there is a single example: bill redness was found to be positively associated with survival and reproductive output in male zebra finches, but negatively so in females. We retested these associations in our captive zebra finch population without two possible limitations of this earlier study. Contrary to the earlier findings, we found no evidence for sexually antagonistic selection. In both sexes, individuals with redder bills showed higher survival. This association disappeared among the females with the reddest bills. Furthermore, females with redder bills achieved higher reproductive output. We conclude that bill redness of male and female zebra finches honestly signals phenotypic quality, and discuss the possible causes of the differences between our results and earlier findings.
-
Sexual selection predicts advancement of avian spring migration in response to climate change
DEFF Research Database (Denmark)
Spottiswoode, Claire N; Tøttrup, Anders P; Coppack, Timothy
2006-01-01
Global warming has led to earlier spring arrival of migratory birds, but the extent of this advancement varies greatly among species, and it remains uncertain to what degree these changes are phenotypically plastic responses or microevolutionary adaptations to changing environmental conditions. We...... suggest that sexual selection could help to understand this variation, since early spring arrival of males is favoured by female choice. Climate change could weaken the strength of natural selection opposing sexual selection for early migration, which would predict greatest advancement in species...... in the timing of first-arriving individuals, suggesting that selection has not only acted on protandrous males. These results suggest that sexual selection may have an impact on the responses of organisms to climate change, and knowledge of a species' mating system might help to inform attempts at predicting...
-
Can sexual selection drive female life histories? A comparative study on Galliform birds
Kolm, N.; Stein, R. W.; Mooers, A. O.; Verspoor, J. J.; Cunningham, E. J. A.
2007-01-01
Sexual selection has been identified as a major evolutionary force shaping male life history traits but its impact on female life history evolution is less clear. Here we examine the impact of sexual selection on three key female traits (body size, egg size and clutch size) in Galliform birds. Using comparative independent contrast analyses and directional DISCRETE analyses, based on published data and a new genera-level supertree phylogeny of Galliform birds, we investigated how sexual selec...
-
Sexual selection on receptor organ traits: younger females attract males with longer antennae
Johnson, Tamara L.; Symonds, Matthew R. E.; Elgar, Mark A.
2017-06-01
Sexual selection theory predicts that female choice may favour the evolution of elaborate male signals. Darwin also suggested that sexual selection can favour elaborate receiver structures in order to better detect sexual signals, an idea that has been largely ignored. We evaluated this unorthodox perspective by documenting the antennal lengths of male Uraba lugens Walker (Lepidoptera: Nolidae) moths that were attracted to experimentally manipulated emissions of female sex pheromone. Either one or two females were placed in field traps for the duration of their adult lives in order to create differences in the quantity of pheromone emissions from the traps. The mean antennal length of males attracted to field traps baited with a single female was longer than that of males attracted to traps baited with two females, a pattern consistent with Darwin's prediction assuming the latter emits higher pheromone concentrations. Furthermore, younger females attracted males with longer antennae, which may reflect age-specific changes in pheromone emission. These field experiments provide the first direct evidence of an unappreciated role for sexual selection in the evolution of sexual dimorphism in moth antennae and raise the intriguing possibility that females select males with longer antennae through strategic emission of pheromones.
-
How sexual selection can drive the evolution of costly sperm ornamentation
Lüpold, Stefan; Manier, Mollie K.; Puniamoorthy, Nalini; Schoff, Christopher; Starmer, William T.; Luepold, Shannon H. Buckley; Belote, John M.; Pitnick, Scott
2016-05-01
Post-copulatory sexual selection (PSS), fuelled by female promiscuity, is credited with the rapid evolution of sperm quality traits across diverse taxa. Yet, our understanding of the adaptive significance of sperm ornaments and the cryptic female preferences driving their evolution is extremely limited. Here we review the evolutionary allometry of exaggerated sexual traits (for example, antlers, horns, tail feathers, mandibles and dewlaps), show that the giant sperm of some Drosophila species are possibly the most extreme ornaments in all of nature and demonstrate how their existence challenges theories explaining the intensity of sexual selection, mating-system evolution and the fundamental nature of sex differences. We also combine quantitative genetic analyses of interacting sex-specific traits in D. melanogaster with comparative analyses of the condition dependence of male and female reproductive potential across species with varying ornament size to reveal complex dynamics that may underlie sperm-length evolution. Our results suggest that producing few gigantic sperm evolved by (1) Fisherian runaway selection mediated by genetic correlations between sperm length, the female preference for long sperm and female mating frequency, and (2) longer sperm increasing the indirect benefits to females. Our results also suggest that the developmental integration of sperm quality and quantity renders post-copulatory sexual selection on ejaculates unlikely to treat male-male competition and female choice as discrete processes.
-
Selective Serotonin Reuptake Inhibitor-Induced Sexual Dysfunction in Adolescents: A Review.
Scharko, Alexander M.
2004-01-01
Objective: To review the existing literature on selective serotonin reuptake inhibitor (SSRI)-induced sexual dysfunction in adolescents. Method: A literature review of SSRI-induced adverse effects in adolescents focusing on sexual dysfunction was done. Nonsexual SSRI-induced adverse effects were compared in adult and pediatric populations.…
-
Sexual selection is influenced by both developmental and adult environments.
Gillespie, Stephanie R; Scarlett Tudor, M; Moore, Allen J; Miller, Christine W
2014-12-01
Sexual selection is often assumed to be strong and consistent, yet increasing research shows it can fluctuate over space and time. Few experimental studies have examined changes in sexual selection in response to natural environmental variation. Here, we use a difference in resource quality to test for the influence of past environmental conditions and current environmental conditions on male and female mate choice and resulting selection gradients for leaf-footed cactus bugs, Narnia femorata. We raised juveniles on natural high- and low-quality diets, cactus pads with and without ripe cactus fruits. New adults were again assigned a cactus pad with or without fruit, paired with a potential mate, and observed for mating behaviors. We found developmental and adult encounter environments affected mating decisions and the resulting patterns of sexual selection for both males and females. Males were not choosy in the low-quality encounter environment, cactus without fruit, but they avoided mating with small females in the high-quality encounter environment. Females were choosy in both encounter environments, avoiding mating with small males. However, they were the choosiest when they were in the low-quality encounter environment. Female mate choice was also context dependent by male developmental environment. Females were more likely to mate with males that had developed on cactus with fruit when they were currently in the cactus with fruit environment. This pattern disappeared when females were in the cactus without fruit environment. Altogether, these results experimentally demonstrate context-dependent mate choice by both males and females. Furthermore, we demonstrate that simple, seasonal changes in resources can lead to fluctuations in sexual selection. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.
-
Sexual differences in telomere selection in the wild.
Olsson, Mats; Pauliny, Angela; Wapstra, Erik; Uller, Tobias; Schwartz, Tonia; Miller, Emily; Blomqvist, Donald
2011-05-01
Telomere length is restored primarily through the action of the reverse transcriptase telomerase, which may contribute to a prolonged lifespan in some but not all species and may result in longer telomeres in one sex than the other. To what extent this is an effect of proximate mechanisms (e.g. higher stress in males, higher oestradiol/oestrogen levels in females), or is an evolved adaptation (stronger selection for telomere length in one sex), usually remains unknown. Sand lizard (Lacerta agilis) females have longer telomeres than males and better maintain telomere length through life than males do. We also show that telomere length more strongly contributes to life span and lifetime reproductive success in females than males and that telomere length is under sexually diversifying selection in the wild. Finally, we performed a selection analysis with number of recruited offspring into the adult population as a response variable with telomere length, life span and body size as predictor variables. This showed significant differences in selection pressures between the sexes with strong ongoing selection in females, with these three predictors explaining 63% of the variation in recruitment. Thus, the sexually dimorphic telomere dynamics with longer telomeres in females is a result of past and ongoing selection in sand lizards. Finally, we compared the results from our selection analyses based on Telometric-derived data to the results based on data generated by the software ImageJ. ImageJ resulted in shorter average telomere length, but this difference had virtually no qualitative effect on the patterns of ongoing selection. © 2011 Blackwell Publishing Ltd.
-
Gray, Lindsey J; Simpson, Stephen J; Polak, Michal
2018-01-01
Optimal life-history strategies are those that best allocate finite environmental resources to competing traits. We used the geometric framework for nutrition to evaluate life-history strategies followed by Drosophila melanogaster by measuring the condition-dependent performance of life-history traits, including the morphology of male secondary sexual characters, sex combs. We found that depending on their rearing environment flies faced different forms of trait trade-offs and accordingly followed different life-history strategies. High-energy, high-carbohydrate, low-protein diets supported development of the largest and most symmetrical sex combs, however, consistent with handicap models of sexual selection these foods were associated with reduced fly survival and developmental rate. Expressing the highest quality sex combs may have required secondary sexual trait quality to be traded-off with developmental rate, and our results indicated that flies unable to slow development died. As larval nutritional environments are predominantly determined by female oviposition substrate choice, we tested where mated female flies laid the most eggs. Mothers chose high-energy, high-protein foods associated with rapid larval development. Mothers avoided high-carbohydrate foods associated with maximal sex comb expression, showing they may avoid producing fewer 'sexy' sons in favour of producing offspring that develop rapidly. Copyright © 2017 Elsevier Ltd. All rights reserved.
-
Sexual minorities and selection of a primary care physician in a midwestern U.S. city.
Labig, Chalmer E; Peterson, Tim O
2006-01-01
How and why sexual minorities select a primary care physician is critical to the development of methods for attracting these clients to a physician's practice. Data obtained from a sample of sexual minorities in a mid-size city in our nation's heartland would indicate that these patients are loyal when the primary care physician has a positive attitude toward their sexual orientation. The data also confirms that most sexual minorities select same sex physicians but not necessarily same sexual orientation physicians because of lack of knowledge of physicians' sexual orientation. Family practice physicians and other primary care physicians can reach out to this population by encouraging word of mouth advertising and by displaying literature on health issues for all sexual orientations in their offices.
-
International Nuclear Information System (INIS)
Sciurano, R.; Rodriguero, M.; Gomez Cendra, P.; Vilardi, J.; Segura, D.; Cladera, J.L.; Allinghi, Armando
2007-01-01
Despite the interest in applying environmentally friendly control methods such as sterile insect technique (SIT) against Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae), information about its biology, taxonomy, and behavior is still insufficient. To increase this information, the present study aims to evaluate the performance of wild flies under field cage conditions through the study of sexual competitiveness among males (sexual selection). A wild population from Horco Molle, Tucuman, Argentina was sampled. Mature virgin males and females were released into outdoor field cages to compete for mating. Morphometric analyses were applied to determine the relationship between the multivariate phenotype and copulatory success. Successful and unsuccessful males were measured for 8 traits: head width (HW), face width (FW), eye length (EL), thorax length (THL), wing length (WL), wing width (WW), femur length (FL), and tibia length (TIL). Combinations of different multivariate statistical methods and graphical analyses were used to evaluate sexual selection on male phenotype. The results indicated that wing width and thorax length would be the most probable targets of sexual selection. They describe a non-linear association between expected fitness and each of these 2 traits. This non-linear relation suggests that observed selection could maintain the diversity related to body size. (author) [es
-
Geography, assortative mating, and the effects of sexual selection on speciation with gene flow.
Servedio, Maria R
2016-01-01
Theoretical and empirical research on the evolution of reproductive isolation have both indicated that the effects of sexual selection on speciation with gene flow are quite complex. As part of this special issue on the contributions of women to basic and applied evolutionary biology, I discuss my work on this question in the context of a broader assessment of the patterns of sexual selection that lead to, versus inhibit, the speciation process, as derived from theoretical research. In particular, I focus on how two factors, the geographic context of speciation and the mechanism leading to assortative mating, interact to alter the effect that sexual selection through mate choice has on speciation. I concentrate on two geographic contexts: sympatry and secondary contact between two geographically separated populations that are exchanging migrants and two mechanisms of assortative mating: phenotype matching and separate preferences and traits. I show that both of these factors must be considered for the effects of sexual selection on speciation to be inferred.
-
Directory of Open Access Journals (Sweden)
Stoyo Karamihalev
2013-08-01
Full Text Available Creativity is an essential human trait, yet there is no consensus among scholars as to why our species have developed creative abilities. Most evolutionary explanations rely on the survival value of such abilities, but generally fail to explain why other species have not evolved similar capacities or why so many human products of creativity have little to no practical value. Sexual selection is an evolutionary force which has the potential to shed new light on this investigation by regarding creativity as a fitness indicator that has evolved for the purposes of courtship and mating. The paper at hand reviews the empirical evidence in support of this hypothesis.
-
Plath, Martin; Riesch, Rüdiger; Oranth, Alexandra; Dzienko, Justina; Karau, Nora; Schießl, Angela; Stadler, Stefan; Wigh, Adriana; Zimmer, Claudia; Arias-Rodriguez, Lenin; Schlupp, Ingo; Tobler, Michael
2010-08-01
Adaptation to ecologically heterogeneous environments can drive speciation. But what mechanisms maintain reproductive isolation among locally adapted populations? Using poeciliid fishes in a system with naturally occurring toxic hydrogen sulfide, we show that (a) fish from non-sulfidic sites ( Poecilia mexicana) show high mortality (95 %) after 24 h when exposed to the toxicant, while locally adapted fish from sulfidic sites ( Poecilia sulphuraria) experience low mortality (13 %) when transferred to non-sulfidic water. (b) Mate choice tests revealed that P. mexicana females exhibit a preference for conspecific males in non-sulfidic water, but not in sulfidic water, whereas P. sulphuraria females never showed a preference. Increased costs of mate choice in sulfidic, hypoxic water, and the lack of selection for reinforcement due to the low survival of P. mexicana may explain the absence of a preference in P. sulphuraria females. Taken together, our study may be the first to demonstrate independent—but complementary—effects of natural and sexual selection against immigrants maintaining differentiation between locally adapted fish populations.
-
The Role of Sexual Selection in the Evolution of Chemical Signals in Insects
Directory of Open Access Journals (Sweden)
Sandra Steiger
2014-06-01
Full Text Available Chemical communication is the most ancient and widespread form of communication. Yet we are only beginning to grasp the complexity of chemical signals and the role they play in sexual selection. Focusing on insects, we review here the recent progress in the field of olfactory-based sexual selection. We will show that there is mounting empirical evidence that sexual selection affects the evolution of chemical traits, but form and strength of selection differ between species. Studies indicate that some chemical signals are expressed in relation to an individual’s condition and depend, for example, on age, immunocompetence, fertility, body size or degree of inbreeding. Males or females might benefit by choosing based on those traits, gaining resources or “good genes”. Other chemical traits appear to reliably reflect an individual’s underlying genotype and are suitable to choose a mating partner that matches best the own genotype.
-
Ramm, Steven A; Khoo, Lin; Stockley, Paula
2010-01-01
The rapid divergence of genitalia is a pervasive trend in animal evolution, thought to be due to the action of sexual selection. To test predictions from the sexual selection hypothesis, we here report data on the allometry, variation, plasticity and condition dependence of baculum morphology in the house mouse (Mus musculus domesticus). We find that that baculum size: (a) exhibits no consistent pattern of allometric scaling (baculum size being in most cases unrelated to body size), (b) exhibits low to moderate levels of phenotypic variation, (c) does not exhibit phenotypic plasticity in response to differences in perceived levels of sexual competition and (d) exhibits limited evidence of condition dependence. These patterns provide only limited evidence in support of the sexual selection hypothesis, and no consistent support for any particular sexual selection mechanism; however, more direct measures of how genital morphology influences male fertilization success are required.
-
Natural Aphrodisiacs-A Review of Selected Sexual Enhancers.
West, Elizabeth; Krychman, Michael
2015-10-01
The Food and Drug Administration defines an aphrodisiac drug product as "any product that bears labeling claims that it will arouse or increase sexual desire, or that it will improve sexual performance." Presently, there are no approved medications for the treatment of lowered desire for women, and many opt for "natural" products. The aim of this article was to review the most popular and currently used aphrodisiac products marketed in the United States. The safety and efficacy of animal- and plant-based aphrodisiacs, vitamins and minerals, and popular over-the-counter combination supplements have been reviewed. An English PubMed literature search was performed using the key words "sexuality," "sex," "aphrodisiac," and "sexual enhancer." Approximately 50 articles were reviewed by the authors. The authors used relevant case series, case-controlled, and randomized clinical trial data. Products were evaluated based on the quality of research, and their known efficacy and safety considerations. Products with low risk and potential benefit for sexual response based on prior research studies were highlighted. Research has demonstrated that the risks of yohimbine, Spanish fly, mad honey, and Bufo toad may outweigh any benefit, and these products should be avoided. Other products, such as Maca, Tribulus, Ginkgo, and ginseng, have limited but emerging data. Randomized clinical trial data are often lacking, but future research should be performed to further elucidate the efficacy and safety of these products. Future randomized clinical trials are warranted before health care practitioners can recommend most aphrodisiac products. There remain some medical concerns with drug interactions, purity, reliability, and safety. West E and Krychman M. Natural aphrodisiacs-A review of selected sexual enhancers.. Copyright © 2015 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.
-
Sexual selection and physical attractiveness : Implications for mating dynamics.
Gangestad, S W
1993-09-01
Sexual selection processes have received much attention in recent years, attention reflected in interest in human mate preferences. Among these mate preferences are preferences for physical attractiveness. Preferences in and of themselves, however, do not fully explain the nature of the relationships that individuals attain. A tacit negotiation process underlies relationship formation and maintenance. The notion that preferences for physical attractiveness evolved under parasite-driven "good genes" sexual selection leads to predictions about the nature of trade-offs that individuals make between mates' physical attractiveness and investment potential. These predictions and relevant data are explored, with a primary emphasis on women's preferences for men's qualities. In addition, further implications of trade-offs are examined, most notably (a) the impact of environmental variations on the nature of mating and (b) some effects of trade-offs on infidelity and male attempts to control women.
-
Rohner, Patrick T; Blanckenhorn, Wolf U; Puniamoorthy, Nalini
2016-06-01
Sexual size dimorphism (SSD) arises when the net effects of natural and sexual selection on body size differ between the sexes. Quantitative SSD variation between taxa is common, but directional intraspecific SSD reversals are rare. We combined micro- and macroevolutionary approaches to study geographic SSD variation in closely related black scavenger flies. Common garden experiments revealed stark intra- and interspecific variation: Sepsis biflexuosa is monomorphic across the Holarctic, while S. cynipsea (only in Europe) consistently exhibits female-biased SSD. Interestingly, S. neocynipsea displays contrasting SSD in Europe (females larger) and North America (males larger), a pattern opposite to the geographic reversal in SSD of S. punctum documented in a previous study. In accordance with the differential equilibrium model for the evolution of SSD, the intensity of sexual selection on male size varied between continents (weaker in Europe), whereas fecundity selection on female body size did not. Subsequent comparative analyses of 49 taxa documented at least six independent origins of male-biased SSD in Sepsidae, which is likely caused by sexual selection on male size and mediated by bimaturism. Therefore, reversals in SSD and the associated changes in larval development might be much more common and rapid and less constrained than currently assumed. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.
-
Rubalcaba, J G; Polo, V; Maia, R; Rubenstein, D R; Veiga, J P
2016-08-01
Although sexual selection is typically considered the predominant force driving the evolution of ritualized sexual behaviours, natural selection may also play an important and often underappreciated role. The use of green aromatic plants among nesting birds has been interpreted as a component of extended phenotype that evolved either via natural selection due to potential sanitary functions or via sexual selection as a signal of male attractiveness. Here, we compared both hypotheses using comparative methods in starlings, a group where this behaviour is widespread. We found that the use of green plants was positively related to male-biased size dimorphism and that it was most likely to occur among cavity-nesting species. These results suggest that this behaviour is likely favoured by sexual selection, but also related to its sanitary use in response to higher parasite loads in cavities. We speculate that the use of green plants in starlings may be facilitated by cavity nesting and was subsequently co-opted as a sexual signal by males. Our results represent an example of how an extended phenotypic component of males becomes sexually selected by females. Thus, both natural selection and sexual selection are necessary to fully understand the evolution of ritualized behaviours involved in courtship. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.
-
Baena, Martha Lucía; Macías-Ordóñez, Rogelio
2012-01-01
Recent debate has highlighted the importance of estimating both the strength of sexual selection on phenotypic traits, and the opportunity for sexual selection. We describe seasonal fluctuations in mating dynamics of Leptinotarsa undecimlineata (Coleoptera: Chrysomelidae). We compared several estimates of the opportunity for, and the strength of, sexual selection and male precopulatory competition over the reproductive season. First, using a null model, we suggest that the ratio between observed values of the opportunity for sexual selections and their expected value under random mating results in unbiased estimates of the actual nonrandom mating behavior of the population. Second, we found that estimates for the whole reproductive season often misrepresent the actual value at any given time period. Third, mating differentials on male size and mobility, frequency of male fighting and three estimates of the opportunity for sexual selection provide contrasting but complementary information. More intense sexual selection associated to male mobility, but not to male size, was observed in periods with high opportunity for sexual selection and high frequency of male fights. Fourth, based on parameters of spatial and temporal aggregation of female receptivity, we describe the mating system of L. undecimlineata as a scramble mating polygyny in which the opportunity for sexual selection varies widely throughout the season, but the strength of sexual selection on male size remains fairly weak, while male mobility inversely covaries with mating success. We suggest that different estimates for the opportunity for, and intensity of, sexual selection should be applied in order to discriminate how different behavioral and demographic factors shape the reproductive dynamic of populations. PMID:22761675
-
Chemical communication, sexual selection, and introgression in wall lizards.
MacGregor, Hannah E A; Lewandowsky, Rachel A M; d'Ettorre, Patrizia; Leroy, Chloé; Davies, Noel W; While, Geoffrey M; Uller, Tobias
2017-10-01
Divergence in communication systems should influence the likelihood that individuals from different lineages interbreed, and consequently shape the direction and rate of hybridization. Here, we studied the role of chemical communication in hybridization, and its contribution to asymmetric and sexually selected introgression between two lineages of the common wall lizard (Podarcis muralis). Males of the two lineages differed in the chemical composition of their femoral secretions. Chemical profiles provided information regarding male secondary sexual characters, but the associations were variable and inconsistent between lineages. In experimental contact zones, chemical composition was weakly associated with male reproductive success, and did not predict the likelihood of hybridization. Consistent with these results, introgression of chemical profiles in a natural hybrid zone resembled that of neutral nuclear genetic markers overall, but one compound in particular (tocopherol methyl ether) matched closely the introgression of visual sexual characters. These results imply that associations among male chemical profiles, sexual characters, and reproductive success largely reflect transient and environmentally driven effects, and that genetic divergence in chemical composition is largely neutral. We therefore suggest that femoral secretions in wall lizards primarily provide information about residency and individual identity rather than function as sexual signals. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.
-
Diploidy and the selective advantage for sexual reproduction in unicellular organisms.
Kleiman, Maya; Tannenbaum, Emmanuel
2009-11-01
This article develops mathematical models describing the evolutionary dynamics of both asexually and sexually reproducing populations of diploid unicellular organisms. The asexual and sexual life cycles are based on the asexual and sexual life cycles in Saccharomyces cerevisiae, Baker's yeast, which normally reproduces by asexual budding, but switches to sexual reproduction when stressed. The mathematical models consider three reproduction pathways: (1) Asexual reproduction, (2) self-fertilization, and (3) sexual reproduction. We also consider two forms of genome organization. In the first case, we assume that the genome consists of two multi-gene chromosomes, whereas in the second case, we consider the opposite extreme and assume that each gene defines a separate chromosome, which we call the multi-chromosome genome. These two cases are considered to explore the role that recombination has on the mutation-selection balance and the selective advantage of the various reproduction strategies. We assume that the purpose of diploidy is to provide redundancy, so that damage to a gene may be repaired using the other, presumably undamaged copy (a process known as homologous recombination repair). As a result, we assume that the fitness of the organism only depends on the number of homologous gene pairs that contain at least one functional copy of a given gene. If the organism has at least one functional copy of every gene in the genome, we assume a fitness of 1. In general, if the organism has l homologous pairs that lack a functional copy of the given gene, then the fitness of the organism is kappa(l). The kappa(l) are assumed to be monotonically decreasing, so that kappa(0) = 1 > kappa(1) > kappa(2) > cdots, three dots, centered > kappa(infinity) = 0. For nearly all of the reproduction strategies we consider, we find, in the limit of large N, that the mean fitness at mutation-selection balance is max{2e(-mu) - 1,0} where N is the number of genes in the haploid set of
-
Alexander, Brenda M; Skinner, Donal C; Roselli, Charles E
2011-01-01
The preference to seek out a sexual partner of the opposite sex is robust and ensures reproduction and survival of the species. Development of female-directed partner preference in the male is dependent on exposure of the developing brain to gonadal steroids synthesized during critical periods of sexual differentiation of the central nervous system. In the absence of androgen exposure, a male-directed partner preference develops. The development and expression of sexual partner preference has been extensively studied in rat, ferret, and sheep model systems. From these models it is clear that gonadal testosterone, often through estrogenic metabolites, cause both masculinization and defeminization of behavior during critical periods of brain development. Changes in the steroid environment during these critical periods result in atypical sexual partner preference. In this manuscript, we review the major findings which support the hypothesis that the organizational actions of sex steroids are responsible for sexual differentiation of sexual partner preferences in select non-human species. We also explore how this information has helped to frame our understanding of the biological influences on human sexual orientation and gender identity.
-
Labonne, Jacques; Hendry, Andrew P
2010-07-01
The standard predictions of ecological speciation might be nuanced by the interaction between natural and sexual selection. We investigated this hypothesis with an individual-based model tailored to the biology of guppies (Poecilia reticulata). We specifically modeled the situation where a high-predation population below a waterfall colonizes a low-predation population above a waterfall. Focusing on the evolution of male color, we confirm that divergent selection causes the appreciable evolution of male color within 20 generations. The rate and magnitude of this divergence were reduced when dispersal rates were high and when female choice did not differ between environments. Adaptive divergence was always coupled to the evolution of two reproductive barriers: viability selection against immigrants and hybrids. Different types of sexual selection, however, led to contrasting results for another potential reproductive barrier: mating success of immigrants. In some cases, the effects of natural and sexual selection offset each other, leading to no overall reproductive isolation despite strong adaptive divergence. Sexual selection acting through female choice can thus strongly modify the effects of divergent natural selection and thereby alter the standard predictions of ecological speciation. We also found that under no circumstances did divergent selection cause appreciable divergence in neutral genetic markers.
-
Terminal investment in multiple sexual signals
DEFF Research Database (Denmark)
Nielsen, Mattias Lange; Holman, Luke
2012-01-01
1. Trade-offs between current and future resource allocation can select for elevated reproductive effort in individuals facing mortality. Males are predicted to benefit from increasing investment in costly sexually selected signals after experiencing an acute life span reduction, although few...... immune challenge in a fashion that made them more attractive to females. 4. The results suggest that males terminally invest in both short- and medium-range pheromones when they perceive reduced future survival. Moreover, the constitutive and inducible aspects of male and female CHC production...
-
Sex-ratio control erodes sexual selection, revealing evolutionary feedback from adaptive plasticity
Fawcett, Tim W.; Kuijper, Bram; Weissing, Franz J.; Pen, Ido
2011-01-01
Female choice is a powerful selective force, driving the elaboration of conspicuous male ornaments. This process of sexual selection has profound implications for many life-history decisions, including sex allocation. For example, females with attractive partners should produce more sons, because
-
Meiotic drive influences the outcome of sexually antagonistic selection at a linked locus.
Patten, M M
2014-11-01
Most meiotic drivers, such as the t-haplotype in Mus and the segregation distorter (SD) in Drosophila, act in a sex-specific manner, gaining a transmission advantage through one sex although suffering only the fitness costs associated with the driver in the other. Their inheritance is thus more likely through one of the two sexes, a property they share with sexually antagonistic alleles. Previous theory has shown that pairs of linked loci segregating for sexually antagonistic alleles are more likely to remain polymorphic and that linkage disequilibrium accrues between them. I probe this similarity between drive and sexual antagonism and examine the evolution of chromosomes experiencing these selection pressures simultaneously. Reminiscent of previous theory, I find that: the opportunity for polymorphism increases for a sexually antagonistic locus that is physically linked to a driving locus; the opportunity for polymorphism at a driving locus also increases when linked to a sexually antagonistic locus; and stable linkage disequilibrium accompanies any polymorphic equilibrium. Additionally, I find that drive at a linked locus favours the fixation of sexually antagonistic alleles that benefit the sex in which drive occurs. Further, I show that under certain conditions reduced recombination between these two loci is selectively favoured. These theoretical results provide clear, testable predictions about the nature of sexually antagonistic variation on driving chromosomes and have implications for the evolution of genomic architecture. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.
-
Fluctuating survival selection explains variation in avian group size.
Brown, Charles R; Brown, Mary Bomberger; Roche, Erin A; O'Brien, Valerie A; Page, Catherine E
2016-05-03
Most animal groups vary extensively in size. Because individuals in certain sizes of groups often have higher apparent fitness than those in other groups, why wide group size variation persists in most populations remains unexplained. We used a 30-y mark-recapture study of colonially breeding cliff swallows (Petrochelidon pyrrhonota) to show that the survival advantages of different colony sizes fluctuated among years. Colony size was under both stabilizing and directional selection in different years, and reversals in the sign of directional selection regularly occurred. Directional selection was predicted in part by drought conditions: birds in larger colonies tended to be favored in cooler and wetter years, and birds in smaller colonies in hotter and drier years. Oscillating selection on colony size likely reflected annual differences in food availability and the consequent importance of information transfer, and/or the level of ectoparasitism, with the net benefit of sociality varying under these different conditions. Averaged across years, there was no net directional change in selection on colony size. The wide range in cliff swallow group size is probably maintained by fluctuating survival selection and represents the first case, to our knowledge, in which fitness advantages of different group sizes regularly oscillate over time in a natural vertebrate population.
-
Rohwer, Sievert; Langston, Nancy; Gori, Dave
1996-10-01
We experimentally manipulated the strength of selection in the field on red-winged blackbirds (Agelaius phoeniceus) to test hypotheses about contrasting selective forces that favor either large or small males in sexually size dimorphic birds. Selander (1972) argued that sexual selection favors larger males, while survival selection eventually stabilizes male size because larger males do not survive as well as smaller males during harsh winters. Searcy (1979a) proposed instead that sexual selection may be self limiting: male size might be stabilized not by overwinter mortality, but by breeding-season sexual selection that favors smaller males. Under conditions of energetic stress, smaller males should be able to display more and thus achieve higher reproductive success. Using feeders that provisioned males or females but not both, we produced conditions that mimicked the extremes of natural conditions. We found experimental support for the hypothesis that when food is abundant, sexual selection favors larger males. But even under conditions of severe energetic stress, smaller males did not gain larger harems, as the self-limiting hypothesis predicted. Larger males were more energetically stressed than smaller males, but in ways that affected their future reproductive output rather than their current reproductive performance. Stressed males that returned had smaller wings and tails than those that did not return; among returning stressed males, relative harem sizes were inversely related to wing and tail length. Thus, male body size may be stabilized not by survival costs during the non-breeding season, nor by energetic costs during the breeding season, but by costs of future reproduction that larger males pay for their increased breeding-season effort. © 1996 The Society for the Study of Evolution.
-
Directory of Open Access Journals (Sweden)
Martha Lucía Baena
Full Text Available Recent debate has highlighted the importance of estimating both the strength of sexual selection on phenotypic traits, and the opportunity for sexual selection. We describe seasonal fluctuations in mating dynamics of Leptinotarsa undecimlineata (Coleoptera: Chrysomelidae. We compared several estimates of the opportunity for, and the strength of, sexual selection and male precopulatory competition over the reproductive season. First, using a null model, we suggest that the ratio between observed values of the opportunity for sexual selections and their expected value under random mating results in unbiased estimates of the actual nonrandom mating behavior of the population. Second, we found that estimates for the whole reproductive season often misrepresent the actual value at any given time period. Third, mating differentials on male size and mobility, frequency of male fighting and three estimates of the opportunity for sexual selection provide contrasting but complementary information. More intense sexual selection associated to male mobility, but not to male size, was observed in periods with high opportunity for sexual selection and high frequency of male fights. Fourth, based on parameters of spatial and temporal aggregation of female receptivity, we describe the mating system of L. undecimlineata as a scramble mating polygyny in which the opportunity for sexual selection varies widely throughout the season, but the strength of sexual selection on male size remains fairly weak, while male mobility inversely covaries with mating success. We suggest that different estimates for the opportunity for, and intensity of, sexual selection should be applied in order to discriminate how different behavioral and demographic factors shape the reproductive dynamic of populations.
-
Sexual selection on land snail shell ornamentation: a hypothesis that may explain shell diversity
Directory of Open Access Journals (Sweden)
Schilthuizen Menno
2003-06-01
Full Text Available Abstract Background Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not previously been explored. Presentation of the hypothesis The hypothesis that is presented consists of two parts. First, that shell ornamentation is the result of sexual selection. Second, that such sexual selection has caused the divergence in shell shape in different species. Testing the hypothesis The first part of the hypothesis may be tested by searching for sexual dimorphism in shell ornamentation in gonochoristic snails, by searching for increased variance in shell ornamentation relative to other shell traits, and by mate choice experiments using individuals with experimentally enhanced ornamentation. The second part of the hypothesis may be tested by comparing sister groups and correlating shell diversity with degree of polygamy. Implications of the hypothesis If the hypothesis were true, it would provide an explanation for the many cases of allopatric evolutionary radiation in snails, where shell diversity cannot be related to any niche differentiation or environmental differences.
-
Menstrual cycle phase alters women's sexual preferences for composers of more complex music.
Charlton, Benjamin D
2014-06-07
Over 140 years ago Charles Darwin first argued that birdsong and human music, having no clear survival benefit, were obvious candidates for sexual selection. Whereas the first contention is now universally accepted, his theory that music is a product of sexual selection through mate choice has largely been neglected. Here, I provide the first, to my knowledge, empirical support for the sexual selection hypothesis of music evolution by showing that women have sexual preferences during peak conception times for men that are able to create more complex music. Two-alternative forced-choice experiments revealed that woman only preferred composers of more complex music as short-term sexual partners when conception risk was highest. No preferences were displayed when women chose which composer they would prefer as a long-term partner in a committed relationship, and control experiments failed to reveal an effect of conception risk on women's preferences for visual artists. These results suggest that women may acquire genetic benefits for offspring by selecting musicians able to create more complex music as sexual partners, and provide compelling support for Darwin's assertion 'that musical notes and rhythm were first acquired by the male or female progenitors of mankind for the sake of charming the opposite sex'.
-
Directory of Open Access Journals (Sweden)
Brenda Mae Alexander
2011-10-01
Full Text Available The preference to seek out a sexual partner of the opposite sex is robust and ensures reproduction and survival of the species. Development of female-directed partner preference in the male is dependent on exposure of the developing brain to gonadal steroids synthesized during critical periods of sexual differentiation of the central nervous system. In the absence of androgen exposure, a male-directed partner preference develops. The development and expression of sexual partner preference has been extensively studied in rats, ferrets, and sheep model systems. From these models it is clear that gonadal testosterone, often through estrogenic metabolites, cause both masculinization and defeminization of behavior during critical periods of brain development. Changes in the steroid environment during these critical periods results in atypical sexual partner preference. In this manuscript, we review the major findings which support the hypothesis that the organizational actions of sex steroids are responsible for sexual differentiation of sexual partner preferences in select non-human species. We also explore how this information has helped to frame our understanding of the biological influences on human sexual orientation and gender identity.
-
The sight of the peacock's tail makes me sick: the early arguments on sexual selection.
Hiraiwa-Hasegawa, M
2000-03-01
Why does a peacock have a beautiful train, while a peahen is sober without such flamboyance? Darwin proposed the theory of sexual selection to explain the differences between the sexes of the same species. Recently the study of sexual selection has been one of the most flourishing areas in evolutionary biology. However, the theory met with great resistance from biologists since the publication of the idea and the history of the theory included a lot of misunderstanding and confusion. There are several reasons for this. First, classical Darwinism failed to recognize social competition as an important selective force. Second, the good-for-the-species argument, which persisted in the days after Darwin, made the sexual selection argument more difficult to under-stand. Compared to the discussions on animals, Darwin's argument on human sex differences is not satisfactory. The reason probably lies in the debate over human racial differences which prevailed in the 19th century.
-
Seasonal change in the opportunity for sexual selection
Czech Academy of Sciences Publication Activity Database
Reichard, Martin; Smith, C.; Bryja, Josef
2008-01-01
Roč. 17, č. 2 (2008), s. 642-651 ISSN 0962-1083 R&D Projects: GA AV ČR KJB600930501 Grant - others:British Ecological Society(GB) ECPG 551/617 Institutional research plan: CEZ:AV0Z60930519 Keywords : bitterling * body size * sexual selection * mating success * reproductive skew Subject RIV: EH - Ecology, Behaviour Impact factor: 5.325, year: 2008 http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1365-294X.2007.03602.x
-
The evolution of autistic-like and schizotypal traits: A sexual selection hypothesis
Directory of Open Access Journals (Sweden)
Marco Del Giudice
2010-08-01
Full Text Available In this paper we present a new hypothesis on the evolution of autistic-like and schizotypal personality traits. We argue that autistic-like and schizotypal traits contribute in opposite ways to individual differences in reproductive and mating strategies, and have been maintained – at least in part – by sexual selection through mate choice. Whereas positive schizotypy can be seen as a psychological phenotype oriented to high mating effort and good genes displays in both sexes, autistic-like traits in their non-pathological form contribute to a male-typical strategy geared toward high parental investment, low mating effort, and long-term resource allocation. At the evolutionary-genetic level, this sexual selection hypothesis is consistent with Crespi and Badcock’s “imprinted brain” theory of autism and psychosis; the effect of offspring mating behavior on resource flow within the family connects sexual selection with genomic imprinting in the context of human biparental care. We conclude by presenting the results of an empirical study testing one of the predictions derived from our hypothesis. In a sample of 200 college students, autistic-like traits predicted lower interest in short-term mating, higher partner-specific investment, and stronger commitment to long-term romantic relations, whereas positive schizotypy showed the opposite pattern of effects.
-
A preference for a sexual signal keeps females safe.
Directory of Open Access Journals (Sweden)
Tae Won Kim
Full Text Available Predation is generally thought to constrain sexual selection by female choice and limit the evolution of conspicuous sexual signals. Under high predation risk, females usually become less choosy, because they reduce their exposure to their predators by reducing the extent of their mate searching. However, predation need not weaken sexual selection if, under high predation risk, females exhibit stronger preferences for males that use conspicuous signals that help females avoid their predators. We tested this prediction in the fiddler crab Uca terpsichores by increasing females' perceived predation risk from crab-eating birds and measuring the attractiveness of a courtship signal that females use to find mates. The sexual signal is an arching mound of sand that males build at the openings of their burrows to which they attract females for mating. We found that the greater the risk, the more attractive were males with those structures. The benefits of mate preferences for sexual signals are usually thought to be linked to males' reproductive contributions to females or their young. Our study provides the first evidence that a female preference for a sexual signal can yield direct survival benefits by keeping females safe as they search for mates.
-
Historical and Experimental Evidence of Sexual Selection for War Heroism
Rusch, H.; Leunissen, J.L.M.; van Vugt, M.
2015-01-01
We report three studies which test a sexual selection hypothesis for male war heroism. Based on evolutionary theories of mate choice we hypothesize that men signal their fitness through displaying heroism in combat. First, we report the results of an archival study on US-American soldiers who fought
-
Directory of Open Access Journals (Sweden)
Cecilia P. Calabuig
2013-08-01
Full Text Available The Coscoroba Swan, Coscoroba coscoroba (Molina, 1782, is a poorly known aberrant Anserine endemic to South America. We captured adult birds (189 male, 157 female from the largest population in Brazil at the Taim Ecological Reserve, State of Rio Grande do Sul, Brazil. Different patterns between sexes can reflect differences in selection, and positive allometry may indicate that a character is sexually selected. We used body weight and 10 morphological measurements to examine allometric differences between males and females of C. coscoroba. Males were consistently larger than females. Analysis of scaling relationships against body mass showed that nostril, tail, wing and bill height were positively allometric (i.e., heavier birds had relatively larger character lengths, but there were no sexual differences in allometric slopes. However, for a given mass, mature females had longer tails, longer wings (up to metacarpophalangeal articulation and shorter heads than males. In the light of current debate in the literature, we discuss whether such positively allometric traits and sexual differences in scaling may be indicative of sexual selection. Although Coscoroba Swan is a monogamous species, increasing the size of some attributes may confer some advantage for mate selection or male-male competition and, contrary to other studies, we suggest that positively allometric slopes alone should not be considered as evidence for sexual selection of the considered traits.
-
Directory of Open Access Journals (Sweden)
Andrey Rudoy
2017-03-01
Full Text Available Sexual size dimorphism (SSD is widespread among animals, with larger females usually attributed to an optimization of resources in reproduction and larger males to sexual selection. A general pattern in the evolution of SSD is Rensch’s rule, which states that SSD increases with body size in species with larger males but decreases when females are larger. We studied the evolution of SSD in the genus Limnebius (Coleoptera, Hydraenidae, measuring SSD and male genital size and complexity of ca. 80% of its 150 species and reconstructing its evolution in a molecular phylogeny with 71 species. We found strong support for a higher evolutionary lability of male body size, which had an overall positive allometry with respect to females and higher evolutionary rates measured over the individual branches of the phylogeny. Increases in SSD were associated to increases in body size, but there were some exceptions with an increase associated to changes in only one sex. Secondary sexual characters (SSC in the external morphology of males appeared several times independently, generally on species that had already increased their size. There was an overall significant correlation between SSD, male body size and male genital size and complexity, although some lineages with complex genitalia had low SSD, and some small species with complex genitalia had no SSD. Our results suggest that the origin of the higher evolutionary variance of male body size may be due to lack of constraints rather than to sexual selection, that may start to act in species with already larger males due to random variation.
-
Coevolution of parental investment and sexually selected traits drives sex-role divergence.
Fromhage, Lutz; Jennions, Michael D
2016-08-18
Sex-role evolution theory attempts to explain the origin and direction of male-female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and/or lower certainty of parentage. However, we overturn the widely cited claim that a negative feedback between the operational sex ratio and the opportunity cost of care selects for egalitarian sex roles. We further argue that our model does not predict any effect of the adult sex ratio (ASR) that is independent of the source of ASR variation. Finally, to increase realism and unify earlier models, we allow for coevolution between parental investment and investment in sexually selected traits. Our model confirms that small initial differences in parental investment tend to increase due to positive evolutionary feedback, formally supporting long-standing, but unsubstantiated, verbal arguments.
-
Sexual selection of human cooperative behaviour: an experimental study in rural Senegal.
Directory of Open Access Journals (Sweden)
Arnaud Tognetti
Full Text Available Human cooperation in large groups and between non-kin individuals remains a Darwinian puzzle. Investigations into whether and how sexual selection is involved in the evolution of cooperation represent a new and important research direction. Here, 69 groups of four men or four women recruited from a rural population in Senegal played a sequential public-good game in the presence of out-group observers, either of the same sex or of the opposite sex. At the end of the game, participants could donate part of their gain to the village school in the presence of the same observers. Both contributions to the public good and donations to the school, which reflect different components of cooperativeness, were influenced by the sex of the observers. The results suggest that in this non-Western population, sexual selection acts mainly on men's cooperative behaviour with non-kin, whereas women's cooperativeness is mainly influenced by nonsexual social selection.
-
Bateman gradients in hermaphrodites: An extended approach to quantify sexual selection.
Anthes, N.; David, P.; Auld, J.R.; Hoffer, J.N.A.; Jarne, P.; Koene, J.M.; Kokko, H.; Lorenzi, M.C.; Pélissié, B.; Sprenger, D.; Staikou, A.; Schärer, L.
2011-01-01
Sexual selection is often quantified using Bateman gradients, which represent sex-specific regression slopes of reproductive success on mating success and thus describe the expected fitness returns from mating more often. Although the analytical framework for Bateman gradients aimed at covering all
-
Sex differences in parental care: Gametic investment, sexual selection, and social environment.
Liker, András; Freckleton, Robert P; Remeš, Vladimir; Székely, Tamás
2015-11-01
Male and female parents often provide different type and amount of care to their offspring. Three major drivers have been proposed to explain parental sex roles: (1) differential gametic investment by males and females that precipitates into sex difference in care, (2) different intensity of sexual selection acting on males and females, and (3) biased social environment that facilitates the more common sex to provide more care. Here, we provide the most comprehensive assessment of these hypotheses using detailed parental care data from 792 bird species covering 126 families. We found no evidence for the gametic investment hypothesis: neither gamete sizes nor gamete production by males relative to females was related to sex difference in parental care. However, sexual selection correlated with parental sex roles, because the male share in care relative to female decreased with both extra-pair paternity and frequency of male polygamy. Parental sex roles were also related to social environment, because male parental care increased with male-biased adult sex ratios (ASRs). Taken together, our results are consistent with recent theories suggesting that gametic investment is not tied to parental sex roles, and highlight the importance of both sexual selection and ASR in influencing parental sex roles. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.
-
Kleene, Kenneth C
2005-01-01
This review proposes that the peculiar patterns of gene expression in spermatogenic cells are the consequence of powerful evolutionary forces known as sexual selection. Sexual selection is generally characterized by intense competition of males for females, an enormous variety of the strategies to maximize male reproductive success, exaggerated male traits at all levels of biological organization, co-evolution of sexual traits in males and females, and conflict between the sexual advantage of the male trait and the reproductive fitness of females and the individual fitness of both sexes. In addition, spermatogenesis is afflicted by selfish genes that promote their transmission to progeny while causing deleterious effects. Sexual selection, selfish genes, and genetic conflict provide compelling explanations for many atypical features of gene expression in spermatogenic cells including the gross overexpression of certain mRNAs, transcripts encoding truncated proteins that cannot carry out basic functions of the proteins encoded by the same genes in somatic cells, the large number of gene families containing paralogous genes encoding spermatogenic cell-specific isoforms, the large number of testis-cancer-associated genes that are expressed only in spermatogenic cells and malignant cells, and the overbearing role of Sertoli cells in regulating the number and quality of spermatozoa.
-
Sexual selection and the evolution of brain size in primates.
Schillaci, Michael A
2006-12-20
Reproductive competition among males has long been considered a powerful force in the evolution of primates. The evolution of brain size and complexity in the Order Primates has been widely regarded as the hallmark of primate evolutionary history. Despite their importance to our understanding of primate evolution, the relationship between sexual selection and the evolutionary development of brain size is not well studied. The present research examines the evolutionary relationship between brain size and two components of primate sexual selection, sperm competition and male competition for mates. Results indicate that there is not a significant relationship between relative brain size and sperm competition as measured by relative testis size in primates, suggesting sperm competition has not played an important role in the evolution of brain size in the primate order. There is, however, a significant negative evolutionary relationship between relative brain size and the level of male competition for mates. The present study shows that the largest relative brain sizes among primate species are associated with monogamous mating systems, suggesting primate monogamy may require greater social acuity and abilities of deception.
-
Quintero-Fong, L; Toledo, J; Ruiz, L; Rendón, P; Orozco-Dávila, D; Cruz, L; Liedo, P
2016-10-01
The sexual performance of Anastrepha ludens males of the Tapachula-7 genetic sexing strain, produced via selection based on mating success, was compared with that of males produced without selection in competition with wild males. Mating competition, development time, survival, mass-rearing quality parameters and pheromone production were compared. The results showed that selection based on mating competitiveness significantly improved the sexual performance of offspring. Development time, survival of larvae, pupae and adults, and weights of larvae and pupae increased with each selection cycle. Differences in the relative quantity of the pheromone compounds (Z)-3-nonenol and anastrephin were observed when comparing the parental males with the F4 and wild males. The implications of this colony management method on the sterile insect technique are discussed.
-
Proximity of signallers can maintain sexual signal variation under stabilizing selection
van Wijk, M.; Heath, J.; Lievers, R.; Schal, C.; Groot, A.T.
2017-01-01
How sexual communication systems can evolve under stabilizing selection is still a paradox in evolutionary biology. In moths, females emit a species-specific sex pheromone, consisting of a blend of biochemically related components, to which males are attracted. Although males appear to exert strong
-
Sexual selection and the adaptive evolution of PKDREJ protein in primates and rodents.
Vicens, Alberto; Gómez Montoto, Laura; Couso-Ferrer, Francisco; Sutton, Keith A; Roldan, Eduardo R S
2015-02-01
PKDREJ is a testis-specific protein thought to be located on the sperm surface. Functional studies in the mouse revealed that loss of PKDREJ has effects on sperm transport and the ability to undergo an induced acrosome reaction. Thus, PKDREJ has been considered a potential target of post-copulatory sexual selection in the form of sperm competition. Proteins involved in reproductive processes often show accelerated evolution. In many cases, this rapid divergence is promoted by positive selection which may be driven, at least in part, by post-copulatory sexual selection. We analysed the evolution of the PKDREJ protein in primates and rodents and assessed whether PKDREJ divergence is associated with testes mass relative to body mass, which is a reliable proxy of sperm competition levels. Evidence of an association between the evolutionary rate of the PKDREJ gene and testes mass relative to body mass was not found in primates. Among rodents, evidence of positive selection was detected in the Pkdrej gene in the family Cricetidae but not in Muridae. We then assessed whether Pkdrej divergence is associated with episodes of sperm competition in these families. We detected a positive significant correlation between the evolutionary rates of Pkdrej and testes mass relative to body mass in cricetids. These findings constitute the first evidence of post-copulatory sexual selection influencing the evolution of a protein that participates in the mechanisms regulating sperm transport and the acrosome reaction, strongly suggesting that positive selection may act on these fertilization steps, leading to advantages in situations of sperm competition. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
-
Sexual differences in post-hatching Saunders's gulls: size, locomotor activity, and foraging skill.
Yoon, Jongmin; Lee, Seung-Hee; Joo, Eun-Jin; Na, Ki-Jeong; Park, Shi-Ryong
2013-04-01
Various selection pressures induce the degree and direction of sexual size dimorphism in animals. Selection favors either larger males for contests over mates or resources, or smaller males are favored for maneuverability; whereas larger females are favored for higher fecundity, or smaller females for earlier maturation for reproduction. In the genus of Larus (seagulls), adult males are generally known to be larger in size than adult females. However, the ontogeny of sexual size dimorphism is not well understood, compared to that in adults. The present study investigates the ontogeny of sexual size dimorphism in Saunders's gulls (Larus saundersi) in captivity. We artificially incubated fresh eggs collected in Incheon, South Korea, and measured body size, locomotor activity, and foraging skill in post-hatching chicks in captivity. Our results indicated that the sexual differences in size and locomotor activity occurred with the post-hatching development. Also, larger males exhibited greater foraging skills for food acquisition than smaller females at 200 days of age. Future studies should assess how the adaptive significance of the sexual size dimorphism in juveniles is linked with sexual divergence in survival rates, intrasexual contests, or parental effort in sexes.
-
Sexually antagonistic selection in human male homosexuality.
Directory of Open Access Journals (Sweden)
Andrea Camperio Ciani
Full Text Available Several lines of evidence indicate the existence of genetic factors influencing male homosexuality and bisexuality. In spite of its relatively low frequency, the stable permanence in all human populations of this apparently detrimental trait constitutes a puzzling 'Darwinian paradox'. Furthermore, several studies have pointed out relevant asymmetries in the distribution of both male homosexuality and of female fecundity in the parental lines of homosexual vs. heterosexual males. A number of hypotheses have attempted to give an evolutionary explanation for the long-standing persistence of this trait, and for its asymmetric distribution in family lines; however a satisfactory understanding of the population genetics of male homosexuality is lacking at present. We perform a systematic mathematical analysis of the propagation and equilibrium of the putative genetic factors for male homosexuality in the population, based on the selection equation for one or two diallelic loci and Bayesian statistics for pedigree investigation. We show that only the two-locus genetic model with at least one locus on the X chromosome, and in which gene expression is sexually antagonistic (increasing female fitness but decreasing male fitness, accounts for all known empirical data. Our results help clarify the basic evolutionary dynamics of male homosexuality, establishing this as a clearly ascertained sexually antagonistic human trait.
-
Sexual selection and the evolution of brain size in primates.
Directory of Open Access Journals (Sweden)
Michael A Schillaci
Full Text Available Reproductive competition among males has long been considered a powerful force in the evolution of primates. The evolution of brain size and complexity in the Order Primates has been widely regarded as the hallmark of primate evolutionary history. Despite their importance to our understanding of primate evolution, the relationship between sexual selection and the evolutionary development of brain size is not well studied. The present research examines the evolutionary relationship between brain size and two components of primate sexual selection, sperm competition and male competition for mates. Results indicate that there is not a significant relationship between relative brain size and sperm competition as measured by relative testis size in primates, suggesting sperm competition has not played an important role in the evolution of brain size in the primate order. There is, however, a significant negative evolutionary relationship between relative brain size and the level of male competition for mates. The present study shows that the largest relative brain sizes among primate species are associated with monogamous mating systems, suggesting primate monogamy may require greater social acuity and abilities of deception.
-
Czech Academy of Sciences Publication Activity Database
Wilkins, M. R.; Karaardic, H.; Vortman, Y.; Parchman, T. L.; Albrecht, Tomáš; Petrželková, Adéla; Özkan, L.; Pap, P. L.; Hubbard, J. K.; Hund, A. K.; Safran, R. J.
2016-01-01
Roč. 29, č. 12 (2016), s. 2410-2421 ISSN 1010-061X R&D Projects: GA MŠk(CZ) LH14045 Institutional support: RVO:68081766 Keywords : birds * natural selection * population genetics * sexual selection & conflicts * speciation Subject RIV: EG - Zoology Impact factor: 2.792, year: 2016
-
Archer, C R; Zajitschek, F; Sakaluk, S K; Royle, N J; Hunt, J
2012-10-01
Recent work suggests that sexual selection can influence the evolution of ageing and lifespan by shaping the optimal timing and relative costliness of reproductive effort in the sexes. We used inbred lines of the decorated cricket, Gryllodes sigillatus, to estimate the genetic (co)variance between age-dependent reproductive effort, lifespan, and ageing within and between the sexes. Sexual selection theory predicts that males should die sooner and age more rapidly than females. However, a reversal of this pattern may be favored if reproductive effort increases with age in males but not in females. We found that male calling effort increased with age, whereas female fecundity decreased, and that males lived longer and aged more slowly than females. These divergent life-history strategies were underpinned by a positive genetic correlation between early-life reproductive effort and ageing rate in both sexes, although this relationship was stronger in females. Despite these sex differences in life-history schedules, age-dependent reproductive effort, lifespan, and ageing exhibited strong positive intersexual genetic correlations. This should, in theory, constrain the independent evolution of these traits in the sexes and may promote intralocus sexual conflict. Our study highlights the importance of sexual selection to the evolution of sex differences in ageing and lifespan in G. sigillatus. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
-
Martel, Michelle M
2013-11-01
Despite the well-established sex difference in prevalence of many childhood and adolescent psychopathological conditions, no integrative metatheory of sex differences in psychopathology exists. This review attempts to provide a metatheoretical framework to guide empirical examination of sex differences in prevalence of childhood-onset "externalizing" and adolescent-onset "internalizing" disorders, based on sexual selection evolutionary theory. Sexual selection theory suggests important between-sex differences in markers, mechanisms, etiology, and developmental timing of risk and resilience relevant to psychopathology. Namely, sexual selection theory hypothesizes that disinhibition and sensation-seeking may be important proximate risk markers for childhood-onset externalizing disorders in males. The theory suggests that these male-biased markers may be a product of their higher exposure to prenatal testosterone, which makes them more susceptible to prenatal stressors with downstream effects on dopaminergic neurotransmission, especially for those with genetic alleles associated with lower dopaminergic function. In contrast, sexual selection theory hypothesizes that negative emotionality, empathy, and cognitive rumination may be important proximate risk markers for adolescent-onset internalizing disorders in females. The theory suggests that these markers are propagated by rapidly rising levels of estradiol at puberty that interact with cortisol and oxytocin. These hormones exert downstream effects on the serotonergic system in such a way as to increase females' sensitivity to interpersonal stressors particularly at puberty and especially for those with lower functional serotonergic activity. Such a metatheory can help integrate prior ideas about sex differences and can also generate new predictions of sex differences in markers, etiology, mechanisms, and developmental timing of common forms of psychopathology. © 2013 American Psychological Association
-
Chen, Xiaohong; Fan, Yanqin; Pouzo, Demian; Ying, Zhiliang
2010-07-01
We study estimation and model selection of semiparametric models of multivariate survival functions for censored data, which are characterized by possibly misspecified parametric copulas and nonparametric marginal survivals. We obtain the consistency and root- n asymptotic normality of a two-step copula estimator to the pseudo-true copula parameter value according to KLIC, and provide a simple consistent estimator of its asymptotic variance, allowing for a first-step nonparametric estimation of the marginal survivals. We establish the asymptotic distribution of the penalized pseudo-likelihood ratio statistic for comparing multiple semiparametric multivariate survival functions subject to copula misspecification and general censorship. An empirical application is provided.
-
Yee, Lesley
2010-10-01
Sexuality has become a medical issue in association with aging. This is due to a number of factors, including increasing age of survival, a positive societal construct that promotes sexuality as important for quality of life as we age, and the medicalisation of sexuality with the advent of prescription medications to treat sexual dysfunction. This article reviews the factors surrounding aging and sexuality and also considers special situations with age, such as institutionalised care and the possibility of elder abuse. Normal physiological changes with aging affect both genders in terms of sexual desire and performance. Other medical conditions increase with age, and these and their treatments will impact on sexuality and the way it can be expressed. Medical practitioners require an understanding of these changes in order to find ways to optimise sexual function in older patients.
-
Rac1 selective activation improves retina ganglion cell survival and regeneration.
Directory of Open Access Journals (Sweden)
Erika Lorenzetto
Full Text Available In adult mammals, after optic nerve injury, retinal ganglion cells (RGCs do not regenerate their axons and most of them die by apoptosis within a few days. Recently, several strategies that activate neuronal intracellular pathways were proposed to prevent such degenerative processes. The rho-related small GTPase Rac1 is part of a complex, still not fully understood, intracellular signaling network, mediating in neurons many effects, including axon growth and cell survival. However, its role in neuronal survival and regeneration in vivo has not yet been properly investigated. To address this point we intravitreally injected selective cell-penetrating Rac1 mutants after optic nerve crush and studied the effect on RGC survival and axonal regeneration. We injected two well-characterized L61 constitutively active Tat-Rac1 fusion protein mutants, in which a second F37A or Y40C mutation confers selectivity in downstream signaling pathways. Results showed that, 15 days after crush, both mutants were able to improve survival and to prevent dendrite degeneration, while the one harboring the F37A mutation also improved axonal regeneration. The treatment with F37A mutant for one month did not improve the axonal elongation respect to 15 days. Furthermore, we found an increase of Pak1 T212 phosphorylation and ERK1/2 expression in RGCs after F37A treatment, whereas ERK1/2 was more activated in glial cells after Y40C administration. Our data suggest that the selective activation of distinct Rac1-dependent pathways could represent a therapeutic strategy to counteract neuronal degenerative processes in the retina.
-
Loehr, Annalise; Doan, Long; Miller, Lisa R
2015-11-01
Empirical research has documented that contact with lesbians and gays is associated with more positive feelings toward and greater support for legal rights for them, but we know less about whether these effects extend to informal aspects of same-sex relationships, such as reactions to public displays of affection. Furthermore, many studies have assumed that contact influences levels of sexual prejudice; however, the possibility of selection effects, in which less sexually prejudiced people have contact, and more sexually prejudiced people do not, raises some doubts about this assumption. We used original data from a nationally representative sample of heterosexuals to determine whether those reporting contact with a lesbian, gay, bisexual, or transgender friend or relative exhibited less sexual prejudice toward lesbian and gay couples than those without contact. This study examined the effect of contact on attitudes toward formal rights and a relatively unexplored dimension, informal privileges. We estimated the effect of having contact using traditional (ordinary least squares regression) methods before accounting for selection effects using propensity score matching. After accounting for selection effects, we found no significant differences between the attitudes of those who had contact and those who did not, for either formal or informal measures. Thus, selection effects appeared to play a pivotal role in confounding the link between contact and sexual prejudice, and future studies should exercise caution in interpreting results that do not account for such selection effects.
-
Holman, Luke; Bro-Jørgensen, Jakob
2016-08-01
Raia et al. propose that the evolution of the shape and complexity of animal ornaments (e.g., deer antlers) can be explained by interspecific variation in body size and is not influenced by sexual selection. They claim to show that ornament complexity is related to body size by an 0.25-power law and argue that this finding precludes a role for sexual selection in the evolution of ornament complexity. However, their study does not test alternative hypotheses and mismeasures antler shape allometry by omitting much of the published data. We show that an index of sexual selection (sexual size dimorphism) is positively correlated with size-corrected antler complexity and that the allometric slope of complexity is substantially greater than 0.25, contra Raia et al. We conclude that sexual selection and physical constraints both affect the evolution of antler shape.
-
Norwegian honey bees surviving Varroa destructor mite infestations by means of natural selection.
Oddie, Melissa A Y; Dahle, Bjørn; Neumann, Peter
2017-01-01
Managed, feral and wild populations of European honey bee subspecies, Apis mellifera , are currently facing severe colony losses globally. There is consensus that the ectoparasitic mite Varroa destructor , that switched hosts from the Eastern honey bee Apis cerana to the Western honey bee A. mellifera , is a key factor driving these losses. For >20 years, breeding efforts have not produced European honey bee colonies that can survive infestations without the need for mite control. However, at least three populations of European honey bees have developed this ability by means of natural selection and have been surviving for >10 years without mite treatments. Reduced mite reproductive success has been suggested as a key factor explaining this natural survival. Here, we report a managed A. mellifera population in Norway, that has been naturally surviving consistent V. destructor infestations for >17 years. Surviving colonies and local susceptible controls were evaluated for mite infestation levels, mite reproductive success and two potential mechanisms explaining colony survival: grooming of adult worker bees and Varroa Sensitive Hygiene (VSH): adult workers specifically detecting and removing mite-infested brood. Mite infestation levels were significantly lower in surviving colonies and mite reproductive success was reduced by 30% when compared to the controls. No significant differences were found between surviving and control colonies for either grooming or VSH. Our data confirm that reduced mite reproductive success seems to be a key factor for natural survival of infested A. mellifera colonies. However, neither grooming nor VSH seem to explain colony survival. Instead, other behaviors of the adult bees seem to be sufficient to hinder mite reproductive success, because brood for this experiment was taken from susceptible donor colonies only. To mitigate the global impact of V. destructor , we suggest learning more from nature, i.e., identifying the obviously
-
Norwegian honey bees surviving Varroa destructor mite infestations by means of natural selection
Directory of Open Access Journals (Sweden)
Melissa A.Y. Oddie
2017-10-01
Full Text Available Background Managed, feral and wild populations of European honey bee subspecies, Apis mellifera, are currently facing severe colony losses globally. There is consensus that the ectoparasitic mite Varroa destructor, that switched hosts from the Eastern honey bee Apis cerana to the Western honey bee A. mellifera, is a key factor driving these losses. For >20 years, breeding efforts have not produced European honey bee colonies that can survive infestations without the need for mite control. However, at least three populations of European honey bees have developed this ability by means of natural selection and have been surviving for >10 years without mite treatments. Reduced mite reproductive success has been suggested as a key factor explaining this natural survival. Here, we report a managed A. mellifera population in Norway, that has been naturally surviving consistent V. destructor infestations for >17 years. Methods Surviving colonies and local susceptible controls were evaluated for mite infestation levels, mite reproductive success and two potential mechanisms explaining colony survival: grooming of adult worker bees and Varroa Sensitive Hygiene (VSH: adult workers specifically detecting and removing mite-infested brood. Results Mite infestation levels were significantly lower in surviving colonies and mite reproductive success was reduced by 30% when compared to the controls. No significant differences were found between surviving and control colonies for either grooming or VSH. Discussion Our data confirm that reduced mite reproductive success seems to be a key factor for natural survival of infested A. mellifera colonies. However, neither grooming nor VSH seem to explain colony survival. Instead, other behaviors of the adult bees seem to be sufficient to hinder mite reproductive success, because brood for this experiment was taken from susceptible donor colonies only. To mitigate the global impact of V. destructor, we suggest learning
-
Roulin, Alexandre
2016-05-01
The signalling function of melanin-based colouration is debated. Sexual selection theory states that ornaments should be costly to produce, maintain, wear or display to signal quality honestly to potential mates or competitors. An increasing number of studies supports the hypothesis that the degree of melanism covaries with aspects of body condition (e.g. body mass or immunity), which has contributed to change the initial perception that melanin-based colour ornaments entail no costs. Indeed, the expression of many (but not all) melanin-based colour traits is weakly sensitive to the environment but strongly heritable suggesting that these colour traits are relatively cheap to produce and maintain, thus raising the question of how such colour traits could signal quality honestly. Here I review the production, maintenance and wearing/displaying costs that can generate a correlation between melanin-based colouration and body condition, and consider other evolutionary mechanisms that can also lead to covariation between colour and body condition. Because genes controlling melanic traits can affect numerous phenotypic traits, pleiotropy could also explain a linkage between body condition and colouration. Pleiotropy may result in differently coloured individuals signalling different aspects of quality that are maintained by frequency-dependent selection or local adaptation. Colouration may therefore not signal absolute quality to potential mates or competitors (e.g. dark males may not achieve a higher fitness than pale males); otherwise genetic variation would be rapidly depleted by directional selection. As a consequence, selection on heritable melanin-based colouration may not always be directional, but mate choice may be conditional to environmental conditions (i.e. context-dependent sexual selection). Despite the interest of evolutionary biologists in the adaptive value of melanin-based colouration, its actual role in sexual selection is still poorly understood.
-
Procter, D S; Moore, A J; Miller, C W
2012-05-01
Sexual selection arises from social interactions, and if social environments vary so too should sexual selection. For example, male-male competition often occurs either in the presence or in the absence of females, and such changes in the social environment could affect the form and strength of sexual selection. Here we examine how the presence of a female influences selection arising from male-male competition in a leaf-footed cactus bug, Narnia femorata, which has a resource defence mating system. Males compete for territories on cacti because females lay eggs on the cactus plants. Females are not always present when this competition first occurs; however, the presence or absence of the female matters. We found that both the form and strength of selection on male traits, those traits that influenced success in intrasexual competition, depended on the social context. When a female was not present, male size and the area of the sexually dimorphic hind legs was only marginally important to winning a contest. However, males with larger overall size and leg area were more likely to win in the presence of a female. There was also positive quadratic selection on these traits when a female was present with both the largest and the smallest males winning. The implication is unexpected alternative strategies when females are present. Our results support the notion that sexual selection should be studied under all relevant social contexts. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.
-
A Combinatory Approach for Selecting Prognostic Genes in Microarray Studies of Tumour Survivals
Directory of Open Access Journals (Sweden)
Qihua Tan
2009-01-01
Full Text Available Different from significant gene expression analysis which looks for genes that are differentially regulated, feature selection in the microarray-based prognostic gene expression analysis aims at finding a subset of marker genes that are not only differentially expressed but also informative for prediction. Unfortunately feature selection in literature of microarray study is predominated by the simple heuristic univariate gene filter paradigm that selects differentially expressed genes according to their statistical significances. We introduce a combinatory feature selection strategy that integrates differential gene expression analysis with the Gram-Schmidt process to identify prognostic genes that are both statistically significant and highly informative for predicting tumour survival outcomes. Empirical application to leukemia and ovarian cancer survival data through-within- and cross-study validations shows that the feature space can be largely reduced while achieving improved testing performances.
-
Sexual Self-Concept and Sexual Risk-Taking.
Breakwell, Glynis M.; Millward, Lynne J.
1997-01-01
Presents data from a survey of randomly selected adolescents (N=474) which examined differences between male and female sexual identities. Results indicate two main dimensions in male sexual self-concept: socioemotional and the relational. Female sexual self-concept revolved around concerns with assertiveness, such as controlling when sex occurs.…
-
Biometric evidence that sexual selection has shaped the hominin face.
Directory of Open Access Journals (Sweden)
Eleanor M Weston
2007-08-01
Full Text Available We consider sex differences in human facial morphology in the context of developmental change. We show that at puberty, the height of the upper face, between the lip and the brow, develops differently in males and females, and that these differences are not explicable in terms of sex differences in body size. We find the same dimorphism in the faces of human ancestors. We propose that the relative shortening in men and lengthening in women of the anterior upper face at puberty is the mechanistic consequence of extreme maxillary rotation during ontogeny. A link between this developmental model and sexual dimorphism is made for the first time, and provides a new set of morphological criteria to sex human crania. This finding has important implications for the role of sexual selection in the evolution of anthropoid faces and for theories of human facial attractiveness.
-
Sex-specific selection under environmental stress in seed beetles.
Martinossi-Allibert, I; Arnqvist, G; Berger, D
2017-01-01
Sexual selection can increase rates of adaptation by imposing strong selection in males, thereby allowing efficient purging of the mutation load on population fitness at a low demographic cost. Indeed, sexual selection tends to be male-biased throughout the animal kingdom, but little empirical work has explored the ecological sensitivity of this sex difference. In this study, we generated theoretical predictions of sex-specific strengths of selection, environmental sensitivities and genotype-by-environment interactions and tested them in seed beetles by manipulating either larval host plant or rearing temperature. Using fourteen isofemale lines, we measured sex-specific reductions in fitness components, genotype-by-environment interactions and the strength of selection (variance in fitness) in the juvenile and adult stage. As predicted, variance in fitness increased with stress, was consistently greater in males than females for adult reproductive success (implying strong sexual selection), but was similar in the sexes in terms of juvenile survival across all levels of stress. Although genetic variance in fitness increased in magnitude under severe stress, heritability decreased and particularly so in males. Moreover, genotype-by-environment interactions for fitness were common but specific to the type of stress, sex and life stage, suggesting that new environments may change the relative alignment and strength of selection in males and females. Our study thus exemplifies how environmental stress can influence the relative forces of natural and sexual selection, as well as concomitant changes in genetic variance in fitness, which are predicted to have consequences for rates of adaptation in sexual populations. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.
-
A mechanism of extreme growth and reliable signaling in sexually selected ornaments and weapons.
Emlen, Douglas J; Warren, Ian A; Johns, Annika; Dworkin, Ian; Lavine, Laura Corley
2012-08-17
Many male animals wield ornaments or weapons of exaggerated proportions. We propose that increased cellular sensitivity to signaling through the insulin/insulin-like growth factor (IGF) pathway may be responsible for the extreme growth of these structures. We document how rhinoceros beetle horns, a sexually selected weapon, are more sensitive to nutrition and more responsive to perturbation of the insulin/IGF pathway than other body structures. We then illustrate how enhanced sensitivity to insulin/IGF signaling in a growing ornament or weapon would cause heightened condition sensitivity and increased variability in expression among individuals--critical properties of reliable signals of male quality. The possibility that reliable signaling arises as a by-product of the growth mechanism may explain why trait exaggeration has evolved so many different times in the context of sexual selection.
-
Sexual practices in Malaysia: determinants of sexual intercourse among unmarried youths.
Zulkifli, S N; Low, W Y
2000-10-01
This paper describes findings on selected determinants of sexual intercourse among 468 unmarried adolescents from a survey in Malaysia. Data on respondents' background, sexual experience, contraceptive use, and sexual attitudes are provided. Based on multiple logistic regressions, factors significantly predictive of sexual experience are gender, employment, and sexual attitudes.
-
Surviving testicular cancer: : sexuality & other existential issues
Pool, Grietje
2003-01-01
The thesis deals with the psychological aspects of ‘sexuality after testicular cancer’, where my collegue, the physician dr. Van Basten formerly predominantly described the physical-biological aspects of this subject. Testicular cancer is a type of male genital cancer, usually diagnosed between
-
Probiotic bacteria: selective enumeration and survival in dairy foods.
Shah, N P
2000-04-01
A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidophilus, Bifidobacterium spp., and Lactobacillus casei. Because of the potential health benefits, these organisms are increasingly incorporated into dairy foods. However, studies have shown low viability of probiotics in market preparations. In order to assess viability of probiotic bacteria, it is important to have a working method for selective enumeration of these probiotic bacteria. Viability of probiotic bacteria is important in order to provide health benefits. Viability of probiotic bacteria can be improved by appropriate selection of acid and bile resistant strains, use of oxygen impermeable containers, two-step fermentation, micro-encapsulation, stress adaptation, incorporation of micronutrients such as peptides and amino acids and by sonication of yogurt bacteria. This review will cover selective enumeration and survival of probiotic bacteria in dairy foods.
-
Jones, A G; Avise, J C
2001-01-01
In pipefishes and seahorses (family Syngnathidae), the males provide all postzygotic care of offspring by brooding embryos on their ventral surfaces. In some species, this phenomenon of male "pregnancy" results in a reversal of the usual direction of sexual selection, such that females compete more than males for access to mates, and secondary sexual characteristics evolve in females. Thus the syngnathids can provide critical tests of theories related to the evolution of sex differences and sexual selection. Microsatellite-based studies of the genetic mating systems of several species of pipefishes and seahorses have provided insights into important aspects of the natural history and evolution of these fishes. First, males of species with completely enclosed pouches have complete confidence of paternity, as might be predicted from parental investment theory for species in which males invest so heavily in offspring. Second, a wide range of genetic mating systems have been documented in nature, including genetic monogamy in a seahorse, polygynandry in two species of pipefish, and polyandry in a third pipefish species. The genetic mating systems appear to be causally related to the intensity of sexual selection, with secondary sex characters evolving most often in females of the more polyandrous species. Third, genetic studies of captive-breeding pipefish suggest that the sexual selection gradient (or Bateman gradient) may be a substantially better method for characterizing the mating system than previously available techniques. Finally, these genetic studies of syngnathid mating systems have led to some general insights into the occurrence of clustered mutations at microsatellite loci, the utility of linked loci in studies of parentage, and the use of parentage data for direct estimation of adult population size.
-
Jones, Adam G.; Walker, DeEtte; Kvarnemo, Charlotta; Lindström, Kai; Avise, John C.
2001-01-01
Alternative mating strategies are common in nature and are generally thought to increase the intensity of sexual selection. However, cuckoldry can theoretically decrease the opportunity for sexual selection, particularly in highly polygamous species. We address here the influence of sneaking (fertilization thievery) on the opportunity for sexual selection in the sand goby Pomatoschistus minutus, a marine fish species in which males build and defend nests. Our microsatellite-based analysis of the mating system in a natural sand goby population shows high rates of sneaking and multiple mating by males. Sneaker males had fertilized eggs in ≈50% of the assayed nests, and multiple sneakers sometimes fertilized eggs from a single female. Successful males had received eggs from 2 to 6 females per nest (mean = 3.4). We developed a simple mathematical model showing that sneaking in this polygynous sand goby population almost certainly decreases the opportunity for sexual selection, an outcome that contrasts with the usual effects of cuckoldry in socially monogamous animals. These results highlight a more complex and interesting relationship between cuckoldry rates and the intensity of sexual selection than previously assumed in much of the literature on animal mating systems. PMID:11481481
-
Crouch, Daniel J M
2017-10-27
The prevalence of sexual reproduction remains mysterious, as it poses clear evolutionary drawbacks compared to reproducing asexually. Several possible explanations exist, with one of the most likely being that finite population size causes linkage disequilibria to randomly generate and impede the progress of natural selection, and that these are eroded by recombination via sexual reproduction. Previous investigations have either analysed this phenomenon in detail for small numbers of loci, or performed population simulations for many loci. Here we present a quantitative genetic model for fitness, based on the Price Equation, in order to examine the theoretical consequences of randomly generated linkage disequilibria when there are many loci. In addition, most previous work has been concerned with the long-term consequences of deleterious linkage disequilibria for population fitness. The expected change in mean fitness between consecutive generations, a measure of short-term evolutionary success, is shown under random environmental influences to be related to the autocovariance in mean fitness between the generations, capturing the effects of stochastic forces such as genetic drift. Interaction between genetic drift and natural selection, due to randomly generated linkage disequilibria, is demonstrated to be one possible source of mean fitness autocovariance. This suggests a possible role for sexual reproduction in reducing the negative effects of genetic drift, thereby improving the short-term efficacy of natural selection. Copyright © 2017 Elsevier Ltd. All rights reserved.
-
DEFF Research Database (Denmark)
Faurby, Søren; Nielsen, Kasper Sauer Kollerup; Bussarawit, Somchai
2011-01-01
. Differences in shape variation between sexes were tested with F-tests, which showed lower intrapopulation morphometric variation in males than females. These results indicate a lower degree of local adaptation on body shape in C. rotundicauda and T. gigas than in L. polyphemus and a lower degree of local......A morphometric analysis of the body shape of three species of horseshoe crabs was undertaken in order to infer the importance of natural and sexual selection. It was expected that natural selection would be most intense, leading to highest regional differentiation, in the American species Limulus...... polyphemus, which has the largest climatic differences between different populations. Local adaptation driven by sexual selection was expected in males but not females because horseshoe crab mating behaviour leads to competition between males, but not between females. Three hundred fifty-nine horseshoe crabs...
-
Directory of Open Access Journals (Sweden)
Shahrbanoo Goli
2016-01-01
Full Text Available The Support Vector Regression (SVR model has been broadly used for response prediction. However, few researchers have used SVR for survival analysis. In this study, a new SVR model is proposed and SVR with different kernels and the traditional Cox model are trained. The models are compared based on different performance measures. We also select the best subset of features using three feature selection methods: combination of SVR and statistical tests, univariate feature selection based on concordance index, and recursive feature elimination. The evaluations are performed using available medical datasets and also a Breast Cancer (BC dataset consisting of 573 patients who visited the Oncology Clinic of Hamadan province in Iran. Results show that, for the BC dataset, survival time can be predicted more accurately by linear SVR than nonlinear SVR. Based on the three feature selection methods, metastasis status, progesterone receptor status, and human epidermal growth factor receptor 2 status are the best features associated to survival. Also, according to the obtained results, performance of linear and nonlinear kernels is comparable. The proposed SVR model performs similar to or slightly better than other models. Also, SVR performs similar to or better than Cox when all features are included in model.
-
Polygyny and extra-pair paternity enhance the opportunity for sexual selection in blue tits
Vedder, Oscar; Komdeur, Jan; van der Velde, Marco; Schut, Elske; Magrath, Michael J. L.
Polygyny and extra-pair paternity are generally thought to enhance sexual selection. However, the extent to which these phenomena increase variance in male reproductive success will depend on the covariance between success at these two strategies. We analysed these patterns over four breeding
-
Males that drop a sexually selected weapon grow larger testes.
Joseph, Paul N; Emberts, Zachary; Sasson, Daniel A; Miller, Christine W
2018-01-01
Costly sexually selected weapons are predicted to trade off with postcopulatory traits, such as testes. Although weapons can be important for achieving access to females, individuals of some species can permanently drop (i.e. autotomize) their weapons, without regeneration, to escape danger. We capitalized on this natural behavior to experimentally address whether the loss of a sexually selected weapon leads to increased testes investment in the leaf-footed cactus bug, Narnia femorata Stål (Hemiptera: Coreidae). In a second experiment, we measured offspring production for males that lost a weapon during development. As predicted, males that dropped a hind limb during development grew significantly larger testes than the control treatments. Hind-limb autotomy did not result in the enlargement of other nearby traits. Our results are the first to experimentally demonstrate that males compensate for natural weapon loss by investing more in testes. In a second experiment we found that females paired with males that lost a hind limb had 40% lower egg hatching success than females paired with intact males, perhaps because of lower mating receptivity to males with a lost limb. Importantly, in those cases where viable offspring were produced, males missing a hind limb produced 42% more offspring than males with intact limbs. These results suggest that the loss of a hind-limb weapon can, in some cases, lead to greater fertilization success. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.
-
Stratton, Terry D; McLaughlin, Margaret A; Witte, Florence M; Fosson, Sue E; Nora, Lois Margaret
2005-04-01
To examine the role of gender discrimination and sexual harassment in medical students' choice of specialty and residency program. Anonymous, self-administered questionnaires were distributed in 1997 to fourth-year students enrolled in 14 public and private U.S. medical schools. In addition to reporting the frequency of gender discrimination and sexual harassment encountered during preclinical coursework, core clerkships, elective clerkships, and residency selection, students assessed the impact of these exposures (none, a little, some, quite a bit, the deciding factor) on their specialty choices and rankings of residency programs. A total of 1,314 (69%) useable questionnaires were returned. Large percentages of men (83.2%) and women (92.8%) experienced, observed, or heard about at least one incident of gender discrimination and sexual harassment during medical school, although more women reported such behavior across all training contexts. Compared with men, significantly (p harassment influenced their specialty choices (45.3% versus 16.4%) and residency rankings (25.3% versus 10.9%). Across all specialties, more women than men experienced gender discrimination and sexual harassment during residency selection, with one exception: a larger percentage of men choosing obstetrics and gynecology experienced such behavior. Among women, those choosing general surgery were most likely to experience gender discrimination and sexual harassment during residency selection. Interestingly, correlations between exposure to gender discrimination and sexual harassment and self-assessed impact on career decisions tended to be larger for men, suggesting that although fewer men are generally affected, they may weigh such experiences more heavily in their choice of specialty and residency program. This study suggests that exposure to gender discrimination and sexual harassment during undergraduate education may influence some medical students' choice of specialty and, to a lesser
-
A change in competitive context reverses sexual selection on male size.
Kasumovic, M M; Andrade, M C B
2009-02-01
In studies of sexual selection, larger size is often argued to increase male fitness, and relatively smaller males are explained by genetic and/or environmental variation. We demonstrate that a size-development life-history trade-off could underlie the maintenance of a broad, unimodal distribution of size in male redback spiders (Latrodectus hasselti). Larger males are superior in direct competition, but redback males mature rapidly at small size in the presence of females. In field enclosures, we simulated two competitive contexts favouring development of divergent male sizes. Relatively smaller males lost when competing directly, but had 10 times higher fitness than relatively larger males when given the temporal advantage of rapid development. Linear selection gradients confirmed the reversal of selection on size, showing that it is critical to consider life-history decisions underlying the development of traits related to fitness.
-
Directory of Open Access Journals (Sweden)
David M. Buss
2013-09-01
Full Text Available Sexual jealousy is a basic emotion. Although it lacks a distinctive facial expression and is unlikely to solve problems of survival, it evolved because it solves adaptive problems of mating. Some adaptive functions are similar in men and women at one level of abstraction, such as warding off potential mate poachers and deterring relationship defection. Other functions are sex-differentiated, such as increasing paternity probability for men and monopolizing a mate's economic commitments for women. Dozens of studies have documented sex-differentiated design features of jealousy: The relative upset about sexual and emotional aspects of infidelity; processing speed and memorial recall of sexual and emotional infidelity cues; physiological distress to sexual and emotional infidelity cues; qualities of same-sex rivals that evoke jealousy, such as superior job prospects versus greater physical attractiveness; triggers of mate retention tactics; jealous interrogations following the discovery of infidelity; and whether an infidelity produces forgiveness or breakup. Although showing all the hallmarks of evolved functionality, sexual jealousy also leads to tremendous destruction, from humiliation to homicide. By these scientific theoretical and empirical criteria, sexual jealousy is properly considered not only "basic" but also "one of the most important emotions".
-
Gallardo-Ortiz, Uriel; Pérez-Staples, Diana; Liedo, Pablo; Toledo, Jorge
2018-04-02
The sterile insect technique (SIT) is used in area-wide pest management programs for establishing low pest prevalence and/or areas free of fruit flies (Diptera: Tephritidae). The aim of this technique is to induce high levels of sterility in the wild population, for this the released insects must have a high sexual competitiveness and field dispersal. However, radiation decreases these biological attributes that do not allow it to compete successfully with wild insects. In this study the sexual competitiveness, field survival and dispersal of Anastrepha obliqua (Macquart; Diptera: Tephritidae) irradiated at 0, 40, 50, 60, 70, and 80 Gy were evaluated in laboratory. A dose of 60 Gy produced 98% sterility, whereas doses of 70 and 80 Gy produced 99% sterility. Sexual competitiveness was assessed in field cages, comparing males irradiated at 0, 50, 60, 70, and 80 Gy against wild males for mating with wild fertile females. Males irradiated at 50 and 60 Gy achieved more matings than those irradiated at 70 and 80 Gy. Wild males were more competitive than mass-reared males, even when these were not irradiated (0 Gy). There was no effect of irradiation on mating latency, yet wild males showed significantly shorter mating latency than mass-reared males. Female remating did not differ among those that mated with wild males and those that mated with males irradiated with different doses. The relative sterility index (RSI) increased from 0.25 at 80 Gy to 0.37 at 60 Gy. The Fried competitiveness index was 0.69 for males irradiated at 70 Gy and 0.57 for those irradiated at 80 Gy, which indicates that a 10 Gy reduction in the irradiation dose produces greater induction of sterility in the wild population. There were no significant differences in field survival and dispersal between flies irradiated at 70 or 80 Gy. Reducing the irradiation dose to 60 or 70 Gy could improve the performance of sterile males and the effectiveness of the SIT. Our results also distinguish between the
-
Raising Darwin's consciousness : Female sexuality and the prehominid origins of patriarchy.
Hrdy, S B
1997-03-01
Sociobiologists and feminists agree that men in patriarchal social systems seek to control females, but sociobiologists go further, using Darwin's theory of sexual selection and Trivers's ideas on parental investment to explain why males should attempt to control female sexuality. From this perspective, the stage for the development under some conditions of patriarchal social systems was set over the course of primate evolution.Sexual selection encompasses both competition between males and female choice. But in applying this theory to our "lower origins" (prehominid ancestors), Darwin assumed that choices were made by essentially "coy" females. I argue here that female solicitation of multiple males (either simultaneously or sequentially, depending on the breeding system) characterized prehominid females; this prehominid legacy of cyclical sexual assertiveness, itself possibly a female counter-strategy to male efforts to control the timing of female reproduction, generated further male counter-strategies. This dialectic had important implications for emerging hominid mating systems, human evolution, and the development of patriarchal arrangements in some human societies. For hominid males who will invest in offspring, there would be powerful selection for emotions, behaviors, and customs that ensure them certainty of paternity. The sexual modesty that so struck Darwin can be explained as a recent evolved or learned (perhaps both) adaptation in women to avoid penalties imposed by patrilines on daughters and mates who failed to conform to the patriline's prevailing norms for their sex. Other supposedly innate universals, such as female preferences for wealthy husbands, are also likely to be facultative accommodations by women to constraints set up when patrilines monopolized resources needed by females to survive and reproduce, and passed on intergenerational control of these resources preferentially to sons.
-
Sexual selection on land snail shell ornamentation: a hypothesis that may explain shell diversity
Schilthuizen, M.
2003-01-01
Background: Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not
-
Alleles versus genotypes: Genetic interactions and the dynamics of selection in sexual populations
Neher, Richard
2010-03-01
Physical interactions between amino-acids are essential for protein structure and activity, while protein-protein interactions and regulatory interactions are central to cellular function. As a consequence of these interactions, the combined effect of two mutations can differ from the sum of the individual effects of the mutations. This phenomenon of genetic interaction is known as epistasis. However, the importance of epistasis and its effects on evolutionary dynamics are poorly understood, especially in sexual populations where recombination breaks up existing combinations of alleles to produce new ones. Here, we present a computational model of selection dynamics involving many epistatic loci in a recombining population. We demonstrate that a large number of polymorphic interacting loci can, despite frequent recombination, exhibit cooperative behavior that locks alleles into favorable genotypes leading to a population consisting of a set of competing clones. As the recombination rate exceeds a certain critical value this ``genotype selection'' phase disappears in an abrupt transition giving way to ``allele selection'' - the phase where different loci are only weakly correlated as expected in sexually reproducing populations. Clustering of interacting sets of genes on a chromosome leads to the emergence of an intermediate regime, where localized blocks of cooperating alleles lock into genetic modules. Large populations attain highest fitness at a recombination rate just below critical, suggesting that natural selection might tune recombination rates to balance the beneficial aspect of exploration of genotype space with the breaking up of synergistic allele combinations.
-
Gender differences in the sexual behaviour of selected adolescents ...
African Journals Online (AJOL)
Using the Falaye Adolescent' Sexual Behaviour Inventory (FASBI), adolescents' sexual behaviour was assessed using the proximate determinants of attitude towards pubertal changes and reproductive biology, adolescent source of sex information, adolescent sexual activities (intercourse and contraception) and attitude ...
-
Barreto, Felipe S.; Avise, John C.
2010-01-01
Taxa in which males alone invest in postzygotic care of offspring are often considered good models for investigating the proffered relationships between sexual selection and mating systems. In the pycnogonid sea spider Pycnogonum stearnsi, males carry large egg masses on their bodies for several weeks, so this species is a plausible candidate for sex-role reversal (greater intensity of sexual selection on females than on males). Here, we couple a microsatellite-based assessment of the mating ...
-
Directory of Open Access Journals (Sweden)
Min Gao
Full Text Available Corneal transplantation is the most used therapy for eye disorders. Although the cornea is somewhat an immune privileged organ, immune rejection is still the major problem that reduces the success rate. Therefore, effective chemical drugs that regulate immunoreactions are needed to improve the outcome of corneal transplantations. Here, a sphingosine-1-phosphate receptor 1 (S1P1 selective agonist was systematically evaluated in mouse allogeneic corneal transplantation and compared with the commonly used immunosuppressive agents. Compared with CsA and the non-selective sphingosine 1-phosphate (S1P receptor agonist FTY720, the S1P1 selective agonist can prolong the survival corneal transplantation for more than 30 days with a low immune response. More importantly, the optimal dose of the S1P1 selective agonist was much less than non-selective S1P receptor agonist FTY720, which would reduce the dose-dependent toxicity in drug application. Then we analyzed the mechanisms of the selected S1P1 selective agonist on the immunosuppression. The results shown that the S1P1 selective agonist could regulate the distribution of the immune cells with less CD4+ T cells and enhanced Treg cells in the allograft, moreover the expression of anti-inflammatory cytokines TGF-β1 and IL-10 unregulated which can reduce the immunoreactions. These findings suggest that S1P1 selective agonist may be a more appropriate immunosuppressive compound to effectively prolong mouse allogeneic corneal grafts survival.
-
Hamzah, Azhar; Thoa, Ngo Phu; Nguyen, Nguyen Hong
2017-11-01
Quantitative genetic analysis was performed on 10,919 data records collected over three generations from the selection programme for increased body weight at harvest in red tilapia (Oreochromis spp.). They were offspring of 224 sires and 226 dams (50 sires and 60 dams per generation, on average). Linear mixed models were used to analyse body traits (weight, length, width and depth), whereas threshold generalised models assuming probit distribution were employed to examine genetic inheritance of survival rate, sexual maturity and body colour. The estimates of heritability for traits studied (body weight, standard length, body width, body depth, body colour, early sexual maturation and survival) across statistical models were moderate to high (0.13-0.45). Genetic correlations among body traits and survival were high and positive (0.68-0.96). Body length and width exhibited negative genetic correlations with body colour (- 0.47 to - 0.25). Sexual maturity was genetically correlated positively with measurements of body traits (weight and length). Direct and correlated genetic responses to selection were measured as estimated breeding values in each generation and expressed in genetic standard deviation units (σ G ). The cumulative improvement achieved for harvest body weight was 1.72 σ G after three generations or 12.5% per generation when the gain was expressed as a percentage of the base population. Selection for improved body weight also resulted in correlated increase in other body traits (length, width and depth) and survival rate (ranging from 0.25 to 0.81 genetic standard deviation units). Avoidance of black spot parent matings also improved the overall red colour of the selected population. It is concluded that the selective breeding programme for red tilapia has succeeded in achieving significant genetic improvement for a range of commercially important traits in this species, and the large genetic variation in body colour and survival also shows that
-
Van Moorter, Bram; Gaillard, Jean-Michel; McLoughlin, Philip D; Delorme, Daniel; Klein, François; Boyce, Mark S
2009-03-01
We examined the relationship between survival of roe deer (Capreolus capreolus) fawns at Trois Fontaines, Champagne-Ardennes, France, and factors related to bed-site selection (predator avoidance and thermoregulation) and maternal food resources (forage availability in the maternal home range). Previous studies have demonstrated that at small scales, the young of large herbivores select bed sites independently from their mothers, although this selection takes place within the limits of their mother's home range. Fawn survival was influenced largely by the availability of good bed sites within the maternal home range, not by the fawn's selection of bed sites; however, selection for thermal cover when selecting bed sites positively influenced survival of young fawns. Typical features of a good home range included close proximity to habitat edges, which is related to forage accessibility for roe deer. The availability of bed sites changed as fawns aged, probably due to an increased mobility of the fawn or a different use of the home range by the mother; sites offering high concealment and thermal protection became less available in favor of areas with higher forage accessibility. Despite the minor influence of bed-site selection on survival, roe deer fawns strongly selected their bed sites according to several environmental factors linked to predator avoidance and thermoregulation. Fawns selected for sites providing concealment, light penetration, and avoided signs of wild boar (Sus scrofa) activity. Avoidance of sites with high light penetration by young fawns positively affected their survival, confirming a negative effect on thermoregulation due to reduced thermal cover. Selection for light penetration by older fawns was less clear. We discuss these results in the context of cross-generational effects in habitat selection across multiple scales, and the potential influence of the 'ghost of predation past'.
-
Barreto, Felipe S; Avise, John C
2010-10-07
Taxa in which males alone invest in postzygotic care of offspring are often considered good models for investigating the proffered relationships between sexual selection and mating systems. In the pycnogonid sea spider Pycnogonum stearnsi, males carry large egg masses on their bodies for several weeks, so this species is a plausible candidate for sex-role reversal (greater intensity of sexual selection on females than on males). Here, we couple a microsatellite-based assessment of the mating system in a natural population with formal quantitative measures of genetic fitness to investigate the direction of sexual selection in P. stearnsi. Both sexes proved to be highly polygamous and showed similar standardized variances in reproductive and mating successes. Moreover, the fertility (number of progeny) of males and females appeared to be equally and highly dependent on mate access, as shown by similar Bateman gradients for the two sexes. The absence of sex-role reversal in this population of P. stearnsi is probably attributable to the fact that males are not limited by brooding space but have evolved an ability to carry large numbers of progeny. Body length was not a good predictor of male mating or reproductive success, so the aim of future studies should be to determine what traits are the targets of sexual selection in this species.
-
Selecting habitat to survive: the impact of road density on survival in a large carnivore.
Directory of Open Access Journals (Sweden)
Mathieu Basille
Full Text Available Habitat selection studies generally assume that animals select habitat and food resources at multiple scales to maximise their fitness. However, animals sometimes prefer habitats of apparently low quality, especially when considering the costs associated with spatially heterogeneous human disturbance. We used spatial variation in human disturbance, and its consequences on lynx survival, a direct fitness component, to test the Hierarchical Habitat Selection hypothesis from a population of Eurasian lynx Lynx lynx in southern Norway. Data from 46 lynx monitored with telemetry indicated that a high proportion of forest strongly reduced the risk of mortality from legal hunting at the home range scale, while increasing road density strongly increased such risk at the finer scale within the home range. We found hierarchical effects of the impact of human disturbance, with a higher road density at a large scale reinforcing its negative impact at a fine scale. Conversely, we demonstrated that lynx shifted their habitat selection to avoid areas with the highest road densities within their home ranges, thus supporting a compensatory mechanism at fine scale enabling lynx to mitigate the impact of large-scale disturbance. Human impact, positively associated with high road accessibility, was thus a stronger driver of lynx space use at a finer scale, with home range characteristics nevertheless constraining habitat selection. Our study demonstrates the truly hierarchical nature of habitat selection, which aims at maximising fitness by selecting against limiting factors at multiple spatial scales, and indicates that scale-specific heterogeneity of the environment is driving individual spatial behaviour, by means of trade-offs across spatial scales.
-
Directory of Open Access Journals (Sweden)
Maria João Fernandes Martins
Full Text Available Assessing the long-term macroevolutionary consequences of sexual selection has been hampered by the difficulty of studying this process in the fossil record. Cytheroid ostracodes offer an excellent system to explore sexual selection in the fossil record because their readily fossilized carapaces are sexually dimorphic. Specifically, males are relatively more elongate than females in this superfamily. This sexual shape difference is thought to arise so that males carapaces can accommodate their very large copulatory apparatus, which can account for up to one-third of body volume. Here we test this widely held explanation for sexual dimorphism in cytheroid ostracodes by correlating investment in male genitalia, a trait in which sexual selection is seen as the main evolutionary driver, with sexual dimorphism of carapace in the genus Cyprideis. We analyzed specimens collected in the field (C. salebrosa, USA; C. torosa, UK and from collections of the National Museum of Natural History, Washington, DC (C. mexicana. We digitized valve outlines in lateral view to obtain measures of size (valve area and shape (elongation, measured as length to height ratio, and obtained several dimensions from two components of the hemipenis: the muscular basal capsule, which functions as a sperm pump, and the section that includes the intromittent organ (terminal extension. In addition to the assessment of this primary sexual trait, we also quantified two dimensions of the male secondary sexual trait-where the transformed right walking leg functions as a clasping organ during mating. We also measured linear dimensions from four limbs as indicators of overall (soft-part body size, and assessed allometry of the soft anatomy. We observed significant correlations in males between valve size, but not elongation, and distinct structural parts of the hemipenis, even after accounting for their shared correlation with overall body size. We also found weak but significant
-
Female responses to experimental removal of sexual selection components in Drosophila melanogaster
Innocenti, Paolo; Flis, Ilona; Morrow, Edward H.
2014-01-01
Background Despite the common assumption that multiple mating should in general be favored in males, but not in females, to date there is no consensus on the general impact of multiple mating on female fitness. Notably, very little is known about the genetic and physiological features underlying the female response to sexual selection pressures. By combining an experimental evolution approach with genomic techniques, we investigated the effects of single and multiple matings on female fecundi...
-
Sztepanacz, Jacqueline L; Rundle, Howard D
2012-10-01
Directional selection is prevalent in nature, yet phenotypes tend to remain relatively constant, suggesting a limit to trait evolution. However, the genetic basis of this limit is unresolved. Given widespread pleiotropy, opposing selection on a trait may arise from the effects of the underlying alleles on other traits under selection, generating net stabilizing selection on trait genetic variance. These pleiotropic costs of trait exaggeration may arise through any number of other traits, making them hard to detect in phenotypic analyses. Stabilizing selection can be inferred, however, if genetic variance is greater among low- compared to high-fitness individuals. We extend a recently suggested approach to provide a direct test of a difference in genetic variance for a suite of cuticular hydrocarbons (CHCs) in Drosophila serrata. Despite strong directional sexual selection on these traits, genetic variance differed between high- and low-fitness individuals and was greater among the low-fitness males for seven of eight CHCs, significantly more than expected by chance. Univariate tests of a difference in genetic variance were nonsignificant but likely have low power. Our results suggest that further CHC exaggeration in D. serrata in response to sexual selection is limited by pleiotropic costs mediated through other traits. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
-
Sexually selected traits: a fundamental framework for studies on behavioral epigenetics.
Jašarević, Eldin; Geary, David C; Rosenfeld, Cheryl S
2012-01-01
Emerging evidence suggests that epigenetic-based mechanisms contribute to various aspects of sex differences in brain and behavior. The major obstacle in establishing and fully understanding this linkage is identifying the traits that are most susceptible to epigenetic modification. We have proposed that sexual selection provides a conceptual framework for identifying such traits. These are traits involved in intrasexual competition for mates and intersexual choice of mating partners and generally entail a combination of male-male competition and female choice. These behaviors are programmed during early embryonic and postnatal development, particularly during the transition from the juvenile to adult periods, by exposure of the brain to steroid hormones, including estradiol and testosterone. We evaluate the evidence that endocrine-disrupting compounds, including bisphenol A, can interfere with the vital epigenetic and gene expression pathways and with the elaboration of sexually selected traits with epigenetic mechanisms presumably governing the expression of these traits. Finally, we review the evidence to suggest that these steroid hormones can induce a variety of epigenetic changes in the brain, including the extent of DNA methylation, histone protein alterations, and even alterations of noncoding RNA, and that many of the changes differ between males and females. Although much previous attention has focused on primary sex differences in reproductive behaviors, such as male mounting and female lordosis, we outline why secondary sex differences related to competition and mate choice might also trace their origins back to steroid-induced epigenetic programming in disparate regions of the brain.
-
An introduction to genetic quality in the context of sexual selection.
Pitcher, Trevor E; Mays, Herman L
2008-09-01
This special issue of Genetica brings together empirical researchers and theoreticians to present the latest on the evolutionary ecology of genetic quality in the context of sexual selection. The work comes from different fields of study including behavioral ecology, quantitative genetics and molecular genetics on a diversity of organisms using different approaches from comparative studies, mathematical modeling, field studies and laboratory experiments. The papers presented in this special issue primarily focus on genetic quality in relation to (1) sources of genetic variation, (2) polyandry, (3) new theoretical developments and (4) comprehensive reviews.
-
McCallum, Malcolm L; Matlock, Makensey; Treas, Justin; Safi, Barroq; Sanson, Wendy; McCallum, Jamie L
2013-12-01
The role that endocrine disruption could play in sexual selection remains relatively untested, and although estrogens occur in insects, little information exists about their biological role in insect reproduction. Atrazine is a commonly applied herbicide that mimics estrogen in vertebrates. Tenebrio molitor were raised from egg to adult under a gradation of environmentally relevant atrazine exposures and a non-treated control. Atrazine was delivered in the drinking water ad libitum. Female T. molitor were provided with a choice between unrelated males raised under three levels of atrazine exposures. Female preference for males demonstrated a non-monotonic inverted U-shaped response to atrazine exposure. There was no significant difference between the control and the high exposure to atrazine. Excluding the control, female preference increased as exposure concentration increased. These results have important repercussions for nonlethal effects of endocrine disruption on populations, their capacity to interfere with sexual selection, and the role of estrogen in pheromone communication among insects.
-
Directory of Open Access Journals (Sweden)
Md Moshiur Rahman
Full Text Available Environmental and ecological conditions can shape the evolution of life history traits in many animals. Among such factors, food or nutrition availability can play an important evolutionary role in moderating an animal's life history traits, particularly sexually selected traits. Here, we test whether diet quantity and/or composition in the form of omega-3 long chain polyunsaturated fatty acids (here termed 'n3LC' influence the expression of pre- and postcopulatory traits in the guppy (Poecilia reticulata, a livebearing poeciliid fish. We assigned males haphazardly to one of two experimental diets supplemented with n3LC, and each of these diet treatments was further divided into two diet 'quantity' treatments. Our experimental design therefore explored the main and interacting effects of two factors (n3LC content and diet quantity on the expression of precopulatory (sexual behaviour and sexual ornamentation, including the size, number and spectral properties of colour spots and postcopulatory (the velocity, viability, number and length of sperm sexually selected traits. Our study revealed that diet quantity had significant effects on most of the pre- and postcopulatory traits, while n3LC manipulation had a significant effect on sperm traits and in particular on sperm viability. Our analyses also revealed interacting effects of diet quantity and n3LC levels on courtship displays, and the area of orange and iridescent colour spots in the males' colour patterns. We also confirmed that our dietary manipulations of n3LC resulted in the differential uptake of n3LC in body and testes tissues in the different n3LC groups. This study reveals the effects of diet quantity and n3LC on behavioural, ornamental and ejaculate traits in P. reticulata and underscores the likely role that diet plays in maintaining the high variability in these condition-dependent sexual traits.
-
Svensson, O; Kvarnemo, C
2003-09-01
Both natural selection and sexual selection may act on nest-building. We tested experimentally how different regimes of egg-predation and male-male competition influence nest-building before mating, using the marine fish sand goby, Pomatoschistus minutus. Males with sneaker males present built the smallest nest-openings, smaller than males held alone or with Pomatoschistus microps males (which may predate eggs and compete over nest-sites but not compete over fertilizations). Males with visual access to other nest-building males tended also to build smaller openings than males held alone or with P. microps. Males with egg-predators present built nests with openings not differing significantly from any other treatment. Our results indicate that the small nest-openings found in the sneaker male treatment are sexually selected through protection against sneaking or by female choice. Across treatments, time span before a male started to build his nest also explained variation in nest-opening width; males starting late built larger nest-openings.
-
The Relationship between Childhood Sexual Abuse and Sexual Dysfunction in Jamaican Adults
Swaby, Antoneal N.; Morgan, Kai A. D.
2009-01-01
This study examined the associations between early traumatic sexualization and later sexual dysfunction in a sample of 100 Jamaican adults while identifying the linkages between age, frequency of abuse, and gender on sexual functioning. Participants were selected via purposive and convenience sampling and divided equally into comparison and…
-
Genomic Signatures of Sexual Conflict.
Kasimatis, Katja R; Nelson, Thomas C; Phillips, Patrick C
2017-10-30
Sexual conflict is a specific class of intergenomic conflict that describes the reciprocal sex-specific fitness costs generated by antagonistic reproductive interactions. The potential for sexual conflict is an inherent property of having a shared genome between the sexes and, therefore, is an extreme form of an environment-dependent fitness effect. In this way, many of the predictions from environment-dependent selection can be used to formulate expected patterns of genome evolution under sexual conflict. However, the pleiotropic and transmission constraints inherent to having alleles move across sex-specific backgrounds from generation to generation further modulate the anticipated signatures of selection. We outline methods for detecting candidate sexual conflict loci both across and within populations. Additionally, we consider the ability of genome scans to identify sexually antagonistic loci by modeling allele frequency changes within males and females due to a single generation of selection. In particular, we highlight the need to integrate genotype, phenotype, and functional information to truly distinguish sexual conflict from other forms of sexual differentiation. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
-
Sexual Selection of Human Cooperative Behaviour: An Experimental Study in Rural Senegal
Tognetti, Arnaud; Berticat, Claire; Raymond, Michel; Faurie, Charlotte
2012-01-01
Human cooperation in large groups and between non-kin individuals remains a Darwinian puzzle. Investigations into whether and how sexual selection is involved in the evolution of cooperation represent a new and important research direction. Here, 69 groups of four men or four women recruited from a rural population in Senegal played a sequential public-good game in the presence of out-group observers, either of the same sex or of the opposite sex. At the end of the game, participants could do...
-
Archer, C.R.; Duffy, E.; Hosken, D.J.; Mokkonen, M.; Okada, K.; Oku, K.; Sharma, M.D.; Hunt, J.
2015-01-01
1. Variation in the strength of age-dependent natural selection shapes differences in ageing rates across species and populations. Likewise, sexual selection can promote divergent patterns of senescence across the sexes. However, the effects of these processes on the evolution of ageing have largely
-
Mutoh, Atsuko; Tokuhara, Shinya; Kanoh, Masayoshi; Oboshi, Tamon; Kato, Shohei; Itoh, Hidenori
It is generally thought that living things have trends in their preferences. The mechanism of occurrence of another trends in successive periods is concerned in their conformity. According to social impact theory, the minority is always exists in the group. There is a possibility that the minority make the transition to the majority by conforming agents. Because of agent's promotion of their conform actions, the majority can make the transition. We proposed an evolutionary model with both genes and memes, and elucidated the interaction between genes and memes on sexual selection. In this paper, we propose an agent model for sexual selection imported the concept of conformity. Using this model we try an environment where male agents and female agents are existed, we find that periodic phenomena of fashion are expressed. And we report the influence of conformity and differentiation on the transition of their preferences.
-
Quantitative genetic models of sexual selection by male choice.
Nakahashi, Wataru
2008-09-01
There are many examples of male mate choice for female traits that tend to be associated with high fertility. I develop quantitative genetic models of a female trait and a male preference to show when such a male preference can evolve. I find that a disagreement between the fertility maximum and the viability maximum of the female trait is necessary for directional male preference (preference for extreme female trait values) to evolve. Moreover, when there is a shortage of available male partners or variance in male nongenetic quality, strong male preference can evolve. Furthermore, I also show that males evolve to exhibit a stronger preference for females that are more feminine (less resemblance to males) than the average female when there is a sexual dimorphism caused by fertility selection which acts only on females.
-
The pathogen transmission avoidance theory of sexual selection
Energy Technology Data Exchange (ETDEWEB)
Loehle, C.
1997-08-01
The current theory that sexual selection results from female preference for males with good genes suffers from several problems. An alternative explanation, the pathogen transmission avoidance hypothesis, argues that the primary function of showy traits is to provide a reliable signal of current disease status, so that sick individuals can be avoided during mating. This study shows that a significant risk of pathogen transmission occurs during mating and that showy traits are reliable indicators of current disease status. The origin of female choosiness is argued to lie in a general tendency to avoid sick individuals, even in the absence of showy traits, which originate as exaggerations of normal traits that are indicative of good health (bright feathers, vigorous movement, large size). Thus, in this new model the origins of both showy traits and female choosiness are not problematic and there is no threshold effect. This model predicts that when the possession of male showy traits does not help to reduce disease in the female, showy traits are unlikely to occur. This case corresponds to thorough exposure of every animal to all group pathogens, on average, in large groups. Such species are shown with a large data set on birds to be less likely to exhibit showy traits. The good-genes model does not make this prediction. The pathogen transmission avoidance model can also lead to the evolution of showy traits even when selection is not effective against a given pathogen (e.g., when there is no heritable variation for resistance), but can result in selection for resistance if such genes are present. Monogamy is argued to reduce selection pressures for showy traits; data show monogamous species to be both less parasitized and less showy. In the context of reduction of pathogen transmission rates in showy populations, selection pressure becomes inversely frequency-dependent, which makes showy traits likely to be self-limiting rather than runaway.
-
Patients' experience of sexuality 1-year after allogeneic Haematopoietic Stem Cell Transplantation
DEFF Research Database (Denmark)
Nørskov, Kristina H; Schmidt, Mette; Jarden, Mary
2015-01-01
body image, which directly or indirectly resulted in sexual dysfunction or problems with intimacy. Symptoms related to chronic GVHD, could explain experiences of sexual dysfunction. Sexual needs were deprioritized as survival became paramount. The experience of changed social roles, both in family life...... sexuality and sexual function one year after HSCT. As symptoms resided, sexuality and sex life became more and more prominent in their thoughts and lives. Increased focus is needed on sexuality and sexual dysfunction in the HSCT clinical setting....
-
Schielzeth, Holger; Streitner, Corinna; Lampe, Ulrike; Franzke, Alexandra; Reinhold, Klaus
2014-12-01
Genome size is largely uncorrelated to organismal complexity and adaptive scenarios. Genetic drift as well as intragenomic conflict have been put forward to explain this observation. We here study the impact of genome size on sexual attractiveness in the bow-winged grasshopper Chorthippus biguttulus. Grasshoppers show particularly large variation in genome size due to the high prevalence of supernumerary chromosomes that are considered (mildly) selfish, as evidenced by non-Mendelian inheritance and fitness costs if present in high numbers. We ranked male grasshoppers by song characteristics that are known to affect female preferences in this species and scored genome sizes of attractive and unattractive individuals from the extremes of this distribution. We find that attractive singers have significantly smaller genomes, demonstrating that genome size is reflected in male courtship songs and that females prefer songs of males with small genomes. Such a genome size dependent mate preference effectively selects against selfish genetic elements that tend to increase genome size. The data therefore provide a novel example of how sexual selection can reinforce natural selection and can act as an agent in an intragenomic arms race. Furthermore, our findings indicate an underappreciated route of how choosy females could gain indirect benefits. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.
-
van der Made, F.; Bloemers, J.; van Ham, D.; El Yassem, W.; Kleiverda, G.; Everaerd, W.; Olivier, B.; Tuiten, A.
2009-01-01
INTRODUCTION: Female sexual dysfunction (FSD) may be associated with reduced central sensitivity for sexual cues. A single dose of testosterone might induce an increase in sensitivity for sexual stimuli, which in turn allows a PDE5 inhibitor to be effective in boosting the physiological sexual
-
[Sexy cancer--sexuality for cancer patients].
Peleg-Nesher, Sharon; Yachini, Brurya; Inbar, Moshe
2009-09-01
Sexuality is a basic need for every human being as long as he or she is alive, irrespective of age or health status. Approximately 23,500 individuals are diagnosed with cancer each year in Israel and join the 120,000 cancer patients currently living in Israel. The results of cancer treatments are traditionally assessed and based on the outcome regarding mortality versus survival. An equally important aspect to be addressed in this assessment must relate to quality of life. One of the more painful insults to the quality of life of cancer patients relates to the deleterious effects on sexuality. This article aims to present physicians with the spectrum of sexuality-related issues which are encountered by cancer patients and their partners, starting from the moment of diagnosis, throughout the various stages of treatment and to provide basic knowledge. Many individuals contracting cancer have difficulty dealing with the issue of sexuality. They are typically embarrassed and feel uneasy when asking health care providers about such a non-life threatening issue. Partners similarly feel both shame and guilt. In many cases sexuality, intimacy and emotional attachment are important aspects and may be essential for survival. Addressing these issues during treatment can provide patients with a sense of security, avoiding embarrassment and further exacerbation of such problems. Unfortunately, little has been done to develop an optimal interventional program, although standard sexual treatments have often been applied. Prospective clinical research and outcomes are missing. The physician can use the well-known PLISSIT model (1978): to provide sexuality involvement on different levels. The very new BETTER model (2004) can help emphasize that cancer treatment and the disease have an influence on intimacy and sexuality.
-
Chesson, Harrell W
2012-03-01
The purpose of this review is to highlight selected studies in the economics literature that address sexually transmitted disease (STD)-related topics that are typically not examined in the STD literature. Two databases (EconLit and Web of Science) were searched to locate STD-related articles in the economics journals. Relevant articles were also identified in other ways, such as informal discussions with colleagues familiar with the literature. To maintain a focus on unique STD-related topics, studies with topics common in the STD literature (e.g., cost-effectiveness, transmission modeling) were excluded. Selected STD-related studies in the economics literature were grouped into the following 8 topics: impact of abortion laws and policies on sexual health outcomes; same-sex marriage and syphilis rates; alcohol policy and STD rates; welfare laws and STD rates; discounting the future; HIV disclosure laws; the impact of tolerance for gays on HIV incidence; and economic versus epidemiologic models of HIV dynamics. A general theme of STD-related studies in the economics literature is that laws and policies that increased the "cost" of risky sex tended to reduce the demand for risky sex, and therefore reduce the incidence of STDs. Economic research can contribute in novel ways to our understanding of influences on risky sexual behavior at the individual level and STD incidence at the population level. Economists and STD experts could mutually benefit from increased collaboration.
-
Best lung function equations for the very elderly selected by survival analysis
DEFF Research Database (Denmark)
Miller, Martin R; Thinggaard, Mikael; Christensen, Kaare
2014-01-01
We evaluated which equations best predicted the lung function of a cohort of nonagenarians based on which best accounted for subsequent survival.In 1998, we measured lung function, grip strength and dementia score (Mini Mental State Examination (MMSE)) in a population-based sample of 2262 Danes...... with a hazard ratio for death of 1, 1.16, 1.32 and 1.60 respectively, compared with equations derived with the inclusion of elderly subjects.We conclude that extrapolating from NHANES III equations to predict lung function in nonagenarians gave better survival predictions from spirometry than when employing...... equations derived using very elderly subjects with possible selection bias. These findings can help inform how future lung function equations for the elderly are derived....
-
Luo, Kun; Kong, Jie; Meng, Xianhong; Luan, Sheng; Cao, Baoxiang; Chen, Baolong
2018-04-01
In this study, families of selected population for growth (SP_BWT), selected population for white spot syndrome virus (WSSV) resistance (SP_RW), Bohai wild population (WP_BH) and Huanghai wild population (WP_HH) of F. chinensis were constructed through artificial insemination and with the standardized procedure of larvae rearing. Growth and survival performance were studied among four populations after a 70 days common test. The results showed that the maximum least square mean of body weight was 17.50 g in SP_BWT while the minimum was 13.03 g in WP_HH. Compared with WP_BH, body weight of SP_BWT increased by 23.41% ( P 0.05). Body weights of SP_BWT and SP_RW were significantly higher than that of WP_HH, which increased by 34.31% ( P populations was 0.19, 0.18, 0.17 and 0.16 g d-1, respectively. Coefficient of variation of body weight among four populations was high, which ranged from 32.67% to 35.25%. Such a range showed that there was the potentiality for further improvement in selected populations. Coefficient of variation of survival rate among four populations was low, varying between 3.20% and 5.90%. The difference of survival was highly significant ( P populations ( P growth performances were also observed among different families in each population. The body weight of 798F family was the highest. The absolute growth rate (AGR) was 0.25 g d-1, 150% higher than that of the lowest one, 0.1 g d-1 in 807F family. Survival rate of families among four populations was different. The highest was 94.74%, and the lowest was 71.88%.
-
[Medical students' sexuality--development and fulfilment of sexual needs].
Müldner-Nieckowski, Łukasz; Klasa, Katarzyna; Sobański, Jerzy A; Rutkowski, Krzysztof; Dembińska, Edyta
2012-01-01
Education in human sexual physiology and pathology, as well as own sexual health of medical doctors determines in a large proportion the ability to talk with patients about their sexual disorders. Therefore the authors considered important to collect and assess data regarding sexual health and development of Medical Faculty students. Analysis of selected aspects of psychosexual development and sex life of IVth grade medical students. We applied the self-report Questionnaire of Satisfaction with Sexual Life (KSS2), an instrument created to assess sexual problems in patients treated with group psychotherapy. Medical students filled the questionnaire when attending the courses of Psychopathology of neurotic disorders or Psychotherapy. Analysis of the collected data revealed a relatively high differentiation of the studied group in regard of satisfaction and experiences with sexual life, attitudes towards masturbation, relationships and sexual activity. Regarding some aspects, significant differences between women and men occurred. A set of factors were identified, some of them may negatively influence medical doctor's competencies in the domain of sexual health. These are not having sexual debut or even lack of any erotic experiences and lack of sexual satisfaction. The results indicate a significant prevalence of factors, which may impede students education as well as taking into consideration the sexual issues during the medical interview. Assessment of influence of students' and doctors' own sexuality on their competencies in diagnostics and treatment requires further studies.
-
Sexual Selection and the Evolution of Human Sex Differences
Directory of Open Access Journals (Sweden)
David C. Geary
2006-12-01
Full Text Available Darwin’s (1871 theory of sexual selection and the associated mechanisms of intrasexual competition (e.g., male-male competition and intersexual choice (e.g., female choice of mates have guided the scientific study of sex differences in hundreds of non-human species. These mechanisms and several recent advances in our understanding of the evolution and expression of sex differences in non-human species are described. The usefulness of this theory for approaching the study human sex differences is illustrated with discussion of patterns of women’s mate preferences and choices and with discussion of men’s one-on-one and coalitional competition. A comparison of these aspects of intersexual choice and intrasexual competition in humans and non-human species is provided, as is discussion of cultural variation in the expression of these behaviors. cultural influences (Maccoby & Jacklin, 1974.
-
No discrimination against previous mates in a sexually cannibalistic spider
Fromhage, Lutz; Schneider, Jutta M.
2005-09-01
In several animal species, females discriminate against previous mates in subsequent mating decisions, increasing the potential for multiple paternity. In spiders, female choice may take the form of selective sexual cannibalism, which has been shown to bias paternity in favor of particular males. If cannibalistic attacks function to restrict a male's paternity, females may have little interest to remate with males having survived such an attack. We therefore studied the possibility of female discrimination against previous mates in sexually cannibalistic Argiope bruennichi, where females almost always attack their mate at the onset of copulation. We compared mating latency and copulation duration of males having experienced a previous copulation either with the same or with a different female, but found no evidence for discrimination against previous mates. However, males copulated significantly shorter when inserting into a used, compared to a previously unused, genital pore of the female.
-
Kingma, Sjouke A.; Szentirmai, Istvan; Szekely, Tamas; Bokony, Veronika; Bleeker, Maarten; Liker, Andras; Komdeur, Jan; McGraw, K.
Melanin-based ornaments are often involved in signaling aggression and dominance, and their role in sexual selection is increasingly recognized. We investigated the functions of a melanin-based plumage ornament (facial 'mask') in male Eurasian penduline tits Remiz pendulinus in the contexts of
-
Rigby, Elizabeth A.; Haukos, David A.
2015-01-01
Mottled ducks (Anas fulvigula) on the western Gulf Coast have exhibited a steep population decline since the mid 1990s. Low rates of breeding incidence and nest success have been implicated in this decline, but duckling survival and the habitat needs of broods have not been previously investigated in this region. We fitted mottled duck ducklings and adult females with radio transmitters and tracked broods to estimate duckling survival and brood habitat selection on the upper Texas Gulf Coast. Duckling survival to 30 days was high (range among models 0.354–0.567) compared to other dabbling duck species. Estimated fecundity was low, (range among models 0.398–0.634) however, indicating that overall reproductive output is low. Within coastal marsh, broods selected home ranges with more water cover and less upland and fresh marsh landcover than was available in the study area. Within coastal marsh home ranges, broods selected for water cover relative to other landcover types, and there was some evidence that broods avoided unvegetated landcover. Although high quality brood habitat is undeniably important, management efforts to increase mottled duck population growth on the western Gulf Coast may best be spent on increasing nesting habitat quality to increase nest success and breeding incidence.
-
A lover or a fighter? Opposing sexual selection pressures on men?s vocal pitch and facial hair
Saxton, Tamsin K.; Mackey, Lauren L.; McCarty, Kristofor; Neave, Nick
2015-01-01
The traditional assumption within the research literature on human sexually dimorphic traits has been that many sex differences have arisen from intersexual selection. More recently however, there has been a shift towards the idea that many male features, including for example male lower-pitched voices, and male beard growth, might have arisen predominantly through intrasexual selection: that is, to serve the purpose of male-male competition instead of mate attraction. In this study, using a ...
-
Ngidi, Ndumiso Daluxolo; Moyo, Sibusiso; Zulu, Thobile; Adam, Jamila Khatoon; Krishna, Suresh Babu Naidu
2016-12-01
The incidence of HIV and AIDS continues to be a source of great concern within universities in South Africa. Furthermore, university students constitute an important community in the intervention against the HIV/AIDS epidemic. Students in the age group of 15-24 years are at a greater risk of HIV infection than any other group in the country; yet, little is known about why they continue to engage in risky sexual practices. This study was designed to explore the sexual behaviour of students in a metropolitan Durban University of Technology in KwaZulu-Natal to understand the social factors underlying their risk of HIV infection. This is a qualitative study that used cluster sampling where the population was stratified by campus and faculty. The study population was selected using a standard randomization technique. This was a part of a multi-phased research project aimed at providing a sero-prevalence baseline and an analysis of risk-taking behaviour at a Durban University of Technology in the eThekwini Metropolitan Municipality area. The study highlights peer pressure among students as an influence in promoting high-risk sexual behaviour. Within this context, the findings revealed that university students lack the ability to negotiate risk-aware decisions especially regarding sexual relationships. This study draws attention to the perspectives of African university students regarding their risk-taking sexual practices and selected factors which influence such behaviour. The findings are not exhaustive in exploring contextual antecedents that shape students' sexual practices. However, they provide an important basis in understanding key factors which expose students to HIV infections. The study provides insights into opportunities for further studies as well as preventative implications.
-
The human sexual response cycle : Brain imaging evidence linking sex to other pleasures
Georgiadis, J. R.; Kringelbach, M. L.
Sexual behavior is critical to species survival, yet comparatively little is known about the neural mechanisms in the human brain. Here we systematically review the existing human brain imaging literature on sexual behavior and show that the functional neuroanatomy of sexual behavior is comparable
-
Directory of Open Access Journals (Sweden)
Hasiah Ayama
2014-06-01
Full Text Available The health benefits of probiotic bacteria have been led to their increasing use in foods. Encapsulation has been investigated to improve their survival. In this study, the selection, encapsulation and viability of lactic acid bacteria (LAB with probiotic properties in simulated gastrointestinal tract (GIT condition were investigated. One hundred and fifty isolates of LAB were obtained from 30 samples of raw cow and goat milk and some fermented foods. Nine isolates could survive under GIT condition and only 3 isolates exhibited an antimicrobial activity against all food-borne pathogenic bacteria. Among them, 2 isolates (CM21 and CM53 exhibited bile salt hydrolase activity on glycocholate and glycodeoxycholate agar plates and were identified as Lactobacillus plantarum. CM53 was selected for encapsulation using 1-3% alginate and 2% Hi-maize resistant starch by emulsion system. Viability and releasing ability of encapsulated CM53 in simulated GIT condition was increased in accordance to the alginate concentration and incubation time, respectively.
-
Sexual and social competition: broadening perspectives by defining female roles.
Rubenstein, Dustin R
2012-08-19
Males figured more prominently than females in Darwin's view of sexual selection. He considered female choice of secondary importance to male-male competition as a mechanism to explain the evolution of male ornaments and armaments. Fisher later demonstrated the importance of female choice in driving male trait evolution, but his ideas were largely ignored for decades. As sexual selection came to embrace the notions of parent-offspring and sexual conflict, and experimental tests of female choice showed promise, females began to feature more prominently in the framework of sexual selection theory. Recent debate over this theory has centred around the role of females, not only over the question of choice, but also over female-female competition. Whereas some have called for expanding the sexual selection framework to encompass all forms of female-female competition, others have called for subsuming sexual selection within a broader framework of social selection, or replacing it altogether. Still others have argued for linking sexual selection more clearly to other evolutionary theories such as kin selection. Rather than simply debating terminology, we must take a broader view of the general processes that lead to trait evolution in both sexes by clearly defining the roles that females play in the process, and by focusing on intra- and inter-sexual interactions in males and females.
-
Guadarrama-Bazante, Irma L; Canseco-Alba, Ana; Rodríguez-Manzo, Gabriela
2014-10-01
Dopamine (DA) plays a central role in the expression of male sexual behavior. The effects of DA-enhancing drugs on copulation seem to vary depending on the dose of the agonist used, the type of DA receptor activated, and the sexual condition of the animals. The aim of the present study was to carry out a systematic analysis of the effects of dopaminergic agonists on the expression of male sexual behavior by sexually competent rats in different sexual motivational states, that is when sexually active (sexually experienced) and when temporarily inhibited (sexually exhausted). To this end, the same doses of the nonselective DA receptor agonist apomorphine, the selective D2-like DA receptor agonist quinpirole, and the selective D1-like DA receptor agonist SKF38393 were injected intraperitoneally to sexually experienced or sexually exhausted male rats and their sexual behavior was recorded. Low apomorphine doses induced expression of sexual behavior in sexually satiated rats, but only reduced the intromission latency of sexually experienced rats. SKF38393 facilitated the expression of sexual behavior by sexually exhausted rats, but not that of sexually experienced males and quinpirole did not exert an effect in both types of animal. In line with these results, the apomorphine-induced reversal of sexual exhaustion was blocked by the D1-like receptor antagonist SCH23390. The data suggest that DA receptors play distinct roles in the expression of sexual behavior by male rats depending on their motivational state and that activation of D1-like receptors promotes the expression of sexual behavior in satiated rats.
-
[Neurobiological foundations underlying normal and disturbed sexuality].
Krüger, T H C; Kneer, J
2017-05-01
Sexual functions are regulated by hormonal and neurochemical factors as well as neuronal networks. An understanding of these basic principles is necessary for the diagnostics, counselling and treatment of sexual problems. Description of essential mechanisms of sexual function on a neurochemical and neuronal level. Literature search, selection and discussion of relevant studies. Analogous to the dual control model there are primary inhibitory (e. g. serotonin) and excitatory neurotransmitter systems (e.g. sex steroids and dopamine). Moreover, neuronal structures have been identified that are responsible for processing sexual stimuli. These networks are altered in subjects with sexual disorders or by pharmacological treatment, e. g. antiandrogens and selective serotonin reuptake inhibitors (SSRI) CONCLUSION: Knowledge of the neurobiology of sexuality forms the foundations for the treatment of sexual dysfunctions in psychiatry and other disciplines.
-
Spada, Eva; Perego, Roberta; Sgamma, Elena Assunta; Proverbio, Daniela
2018-02-01
Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are among the most important feline infectious diseases worldwide. This retrospective study investigated survival times and effects of selected predictor factors on survival time in a population of owned pet cats in Northern Italy testing positive for the presence of FIV antibodies and FeLV antigen. One hundred and three retrovirus-seropositive cats, 53 FIV-seropositive cats, 40 FeLV-seropositive cats, and 10 FIV+FeLV-seropositive cats were included in the study. A population of 103 retrovirus-seronegative age and sex-matched cats was selected. Survival time was calculated and compared between retrovirus-seronegative, FIV, FeLV and FIV+FeLV-seropositive cats using Kaplan-Meier survival analysis. Cox proportional-hazards regression analysis was used to study the effect of selected predictor factors (male gender, peripheral blood cytopenia as reduced red blood cells - RBC- count, leukopenia, neutropenia and lymphopenia, hypercreatininemia and reduced albumin to globulin ratio) on survival time in retrovirus-seropositive populations. Median survival times for seronegative cats, FIV, FeLV and FIV+FeLV-seropositive cats were 3960, 2040, 714 and 77days, respectively. Compared to retrovirus-seronegative cats median survival time was significantly lower (P<0.000) in FeLV and FIV+FeLV-seropositive cats. Median survival time in FeLV and FIV+FeLV-seropositive cats was also significant lower (P<0.000) when compared to FIV-seropositive cats. Hazard ratio of death in FeLV and FIV+FeLV-seropositive cats being respectively 3.4 and 7.4 times higher, in comparison to seronegative cats and 2.3 and 4.8 times higher in FeLV and FIV+FeLV-seropositive cats as compared to FIV-seropositive cats. A Cox proportional-hazards regression analysis showed that FIV and FeLV-seropositive cats with reduced RBC counts at time of diagnosis of seropositivity had significantly shorter survival times when compared to FIV and Fe
-
Directory of Open Access Journals (Sweden)
M. Theau.Clément
2015-09-01
Full Text Available Sexual receptivity of rabbit does at insemination greatly influences fertility and is generally induced by hormones or techniques known as “biostimulation”. Searching for more sustainable farming systems, an original alternative would be to utilise the genetic pathway to increase the does’receptivity. The purpose of the present study was to identify genetic and non-genetic factors that influence rabbit doe sexual receptivity, in the context of a divergent selection experiment over 1 generation. The experiment spanned 2 generations: the founder generation (G0 consisting of 140 rabbit does, and the G1 generation comprising 2 divergently selected lines (L and H lines with 70 does each and 2 successive batches from each generation. The selection rate of the G0 females to form the G1 lines was 24/140. The selection tests consisted of 16 to 18 successive receptivity tests at the rate of 3 tests per week. On the basis of 4716 tests from 275 females, the average receptivity was 56.6±48.2%. A batch effect and a test operator effect were revealed. The contribution of females to the total variance was 20.0%, whereas that of bucks was only 1.1%. Throughout the experiment, 18.2% of does expressed a low receptivity (< 34%, 50.7% a medium one and 33.1% a high one (>66%. Some does were frequently receptive, whereas others were rarely receptive. The repeatability of sexual receptivity was approximately 20%. The results confirmed the high variability of sexual receptivity of non-lactating rabbit does maintained without any biostimulation or hormonal treatment. A lack of selection response on receptivity was observed. Accordingly, the heritability of receptivity was estimated at 0.01±0.02 from an animal model and at 0.02±0.03 from a sire and dam model. The heritability of the average receptivity of a doe was calculated as 0.04. In agreement with the low estimated heritability, the heritability determined was no different from zero
-
Friendship, sexual intimacy and young people's negotiations of sexual health.
Byron, Paul
2017-04-01
This paper examines how young people's friendships influence safer sexual practices. Through a thematic discourse analysis, interviews with Sydney-based young people (aged 18-25 years) and Australian-based sexual health websites for young people are considered. Interview data illustrate how friendships can support young people's sexual experiences, concerns and safeties beyond the practice of 'safe sex' (condom use). This is evident in friends' practices of sex and relationship advice, open dialogue, trust and sharing experiential knowledge, as well as friend-based sex. Meanwhile, friendship discourse from selected Australian sexual health websites fails to engage with the support offered by friendship, or its value to a sexual health agenda. Foucault's account of friendship as a space of self-invention is considered in light of these data, along with his argument that friendship poses a threat to formal systems of knowing and regulating sex. Whether sexual or not, many close friendships are sexually intimate given the knowledge, support and influence these offer to one's sexual practices and relations. This paper argues that greater attention to friendship among sexual health promoters and researchers would improve professional engagements with young people's contemporary sexual cultures, and better inform their attempts to engage young people through social media.
-
Generalized structural equations improve sexual-selection analyses.
Directory of Open Access Journals (Sweden)
Sonia Lombardi
Full Text Available Sexual selection is an intense evolutionary force, which operates through competition for the access to breeding resources. There are many cases where male copulatory success is highly asymmetric, and few males are able to sire most females. Two main hypotheses were proposed to explain this asymmetry: "female choice" and "male dominance". The literature reports contrasting results. This variability may reflect actual differences among studied populations, but it may also be generated by methodological differences and statistical shortcomings in data analysis. A review of the statistical methods used so far in lek studies, shows a prevalence of Linear Models (LM and Generalized Linear Models (GLM which may be affected by problems in inferring cause-effect relationships; multi-collinearity among explanatory variables and erroneous handling of non-normal and non-continuous distributions of the response variable. In lek breeding, selective pressure is maximal, because large numbers of males and females congregate in small arenas. We used a dataset on lekking fallow deer (Dama dama, to contrast the methods and procedures employed so far, and we propose a novel approach based on Generalized Structural Equations Models (GSEMs. GSEMs combine the power and flexibility of both SEM and GLM in a unified modeling framework. We showed that LMs fail to identify several important predictors of male copulatory success and yields very imprecise parameter estimates. Minor variations in data transformation yield wide changes in results and the method appears unreliable. GLMs improved the analysis, but GSEMs provided better results, because the use of latent variables decreases the impact of measurement errors. Using GSEMs, we were able to test contrasting hypotheses and calculate both direct and indirect effects, and we reached a high precision of the estimates, which implies a high predictive ability. In synthesis, we recommend the use of GSEMs in studies on
-
Caccamo, Alexandra; Kachur, Rachel; Williams, Samantha P
2017-08-01
Homelessness affects an estimated 1.6 million US youth annually. Compared with housed youth, homeless youth are more likely to engage in high-risk behaviors, including inconsistent condom use, multiple sex partners, survival sex, and alcohol/drug use, putting them at increased sexually transmitted disease (STD) risk. However, there is no national estimate of STD prevalence among this population. We identified 10 peer-reviewed articles (9 unique studies) reporting STD prevalence among homeless US youth (2000-2015). Descriptive and qualitative analyses identified STD prevalence ranges and risk factors among youth. Eight studies reported specific STD prevalence estimates, mainly chlamydia, gonorrhea, and syphilis. Overall STD prevalence among homeless youth ranged from 6% to 32%. STD rates for girls varied from 16.7% to 46%, and from 9% to 13.1% in boys. Most studies were conducted in the Western United States, with no studies from the Southeast or Northeast. Youths who experienced longer periods of homelessness were more likely to engage in high-risk sexual behaviors. Girls had lower rates of condom use and higher rates of STDs; boys were more likely to engage in anal and anonymous sex. Additionally, peer social networks contributed to protective effects on individual sexual risk behavior. Sexually transmitted disease prevalence estimates among homeless youth fluctuated greatly by study. Sexually transmitted disease risk behaviors are associated with unmet survival needs, length of homelessness, and influence of social networks. To promote sexual health and reduce STD rates, we need better estimates of STD prevalence, more geographic diversity of studies, and interventions addressing the behavioral associations identified in our review.
-
Hunting promotes sexual conflict in brown bears.
Gosselin, Jacinthe; Leclerc, Martin; Zedrosser, Andreas; Steyaert, Sam M J G; Swenson, Jon E; Pelletier, Fanie
2017-01-01
The removal of individuals through hunting can destabilize social structure, potentially affecting population dynamics. Although previous studies have shown that hunting can indirectly reduce juvenile survival through increased sexually selected infanticide (SSI), very little is known about the spatiotemporal effects of male hunting on juvenile survival. Using detailed individual monitoring of a hunted population of brown bears (Ursus arctos) in Sweden (1991-2011), we assessed the spatiotemporal effect of male removal on cub survival. We modelled cub survival before, during and after the mating season. We used three proxies to evaluate spatial and temporal variation in male turnover; distance and timing of the closest male killed and number of males that died around a female's home range centre. Male removal decreased cub survival only during the mating season, as expected in seasonal breeders with SSI. Cub survival increased with distance to the closest male killed within the previous 1·5 years, and it was lower when the closest male killed was removed 1·5 instead of 0·5 year earlier. We did not detect an effect of the number of males killed. Our results support the hypothesis that social restructuring due to hunting can reduce recruitment and suggest that the distribution of the male deaths might be more important than the overall number of males that die. As the removal of individuals through hunting is typically not homogenously distributed across the landscape, spatial heterogeneity in hunting pressure may cause source-sink dynamics, with lower recruitment in areas of high human-induced mortality. © 2016 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.
-
ParSel: Parallel Selection of Micro-RNAs for Survival Classification in Cancers.
Sinha, Debajyoti; Sengupta, Debarka; Bandyopadhyay, Sanghamitra
2017-07-01
It is known that tumor micro-RNAs (miRNA) can define patient survival and treatment response. We present a framework to identify miRNAs which are predictive of cancer survival. The framework attempts to rank the miRNAs by exploring their collaborative role in gene regulation. Our approach tests a significantly large number of combinatorial cases leveraging parallel computation. We carefully avoided parametric assumptions involved in evaluations of miRNA expressions but used rigorous statistical computation to assign an importance score to a miRNA. Experimental results on three cancer types namely, KIRC, OV and GBM verify that the top ranked miRNAs obtained using the proposed framework produce better classification accuracy as compared to some best practice variable selection methods. Some of these top ranked miRNA are also known to be associated with related diseases. © 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim.
-
Townsend, J M; Levy, G D
1990-04-01
Male (n = 170) and female (n = 212) college students viewed photographs, which had been prerated for physical attractiveness, of three opposite-sex individuals. These photographs were paired with three levels of occupational status and income. Subjects indicated their willingness to engage in relationships of varying levels of sexual intimacy and marital potential with the portrayed individuals. Analyses of variance, correlations, and trend analyses supported the hypotheses. Compared to men, women are more likely to prefer or insist that sexual intercourse occur in relationships that involve affection and marital potential, and women place more emphasis than men do on partners' SES in such relationships. Consequently, men's SES and their willingness and ability to invest affection and resources in relationships may often outweigh the effects of their physical attractiveness in women's actual selection of partners. These results and the literature reviewed are more consistent with parental investment theory than with the view that these sex differences are solely the result of differential access to resources and differential socialization.
-
Structural adaptations to diverse fighting styles in sexually selected weapons.
McCullough, Erin L; Tobalske, Bret W; Emlen, Douglas J
2014-10-07
The shapes of sexually selected weapons differ widely among species, but the drivers of this diversity remain poorly understood. Existing explanations suggest weapon shapes reflect structural adaptations to different fighting styles, yet explicit tests of this hypothesis are lacking. We constructed finite element models of the horns of different rhinoceros beetle species to test whether functional specializations for increased performance under species-specific fighting styles could have contributed to the diversification of weapon form. We find that horns are both stronger and stiffer in response to species-typical fighting loads and that they perform more poorly under atypical fighting loads, which suggests weapons are structurally adapted to meet the functional demands of fighting. Our research establishes a critical link between weapon form and function, revealing one way male-male competition can drive the diversification of animal weapons.
-
Allan, George F; Tannenbaum, Pamela; Sbriscia, Tifanie; Linton, Olivia; Lai, Muh-Tsann; Haynes-Johnson, Donna; Bhattacharjee, Sheela; Zhang, Xuqing; Sui, Zhihua; Lundeen, Scott G
2007-08-01
Androgen receptor (AR) ligands with tissue selectivity (selective androgen receptor modulators, or SARMs) have potential for treating muscle wasting, hypogonadism of aging, osteoporosis, female sexual dysfunction, and other indications. JNJ-28330835 is a nonsteroidal AR ligand with mixed agonist and antagonist activity in androgen-responsive cell-based assays. It is an orally active SARM with muscle selectivity in orchidectomized rat models. It stimulated growth of the levator ani muscle, stimulating maximal growth at a dose of 10 mg/kg. At the same time, JNJ-28330835 reduced prostate weight in intact rats by a mean of 30% at 10 mg/kg, while having no inhibitory effect on muscle. Using magnetic resonance imaging (MRI) to monitor body composition, it prevented half of the loss of lean body mass associated with orchidectomy, and restored about 30% of lost lean mass to aged orchidectomized rats. It had agonist effects on markers of both osteoclast and osteoblast activity, suggesting that it reduces bone turnover. In a model of sexual behavior, JNJ-28330835 enhanced the preference of ovariectomized female rats for sexually intact male rats over nonsexual orchidectomized males. JNJ-28330835 is a prostate-sparing SARM with the potential for clinically beneficial effects in muscle-wasting diseases and sexual function disorders.
-
Verweij, K.J.H.; Burri, A.V.; Zietsch, B.P.
2014-01-01
Sexual selection can cause evolution in traits that affect mating success, and it has thus been implicated in the evolution of human physical and behavioural traits that influence attractiveness. We use a large sample of identical and nonidentical female twins to test the prediction from mate choice
-
Genetic constraints and sexual dimorphism in immune defense
DEFF Research Database (Denmark)
Rolff, Jens; Armitage, Sophie Alice Octavia; Coltman, David W.
2005-01-01
The absence of continued evolutionary change despite the presence of genetic variation and directional selection is very common. Genetic correlations between traits can reduce the evolvability of traits. One intriguing example might be found in a sexual conflict over sexually dimorphic traits......: a common genetic architecture constrains the response to selection on a trait subjected to sexually asymmetric selection pressures. Here we show that males and females of the mealworm beetle Tenebrio molitor differ in the quantitative genetic architecture of four traits related to immune defense...
-
Gender Differences In Premarital Sexual Permissiveness Among ...
African Journals Online (AJOL)
This paper examined the concept of premariatal sexual permissiveness among selected University undergraduates in a state owned university in Nigeria, believing that the policy of non-residential status of the University will facilitate premarital sexual activity among the students. Using a total of 400 purposively selected ...
-
Sexual risk behavior and type of sexual partners in transnational indigenous migrant workers.
Caballero-Hoyos, Ramiro; Villaseñor-Sierra, Alberto; Millán-Guerrero, Rebeca; Trujillo-Hernández, Benjamín; Monárrez-Espino, Joel
2013-06-01
Indigenous migrant workers (IMWs) have a high vulnerability to HIV and STDs due to poverty and marginalization. This study examined factors associated with sexual risk behavior (SRB) according to type of partner in transnational young male IMWs at a sugar cane agro-industrial complex in western Mexico. A total of 192 sexually active IMWs were recruited from four laborer shelters to participate in a sexual partner survey. The IMWs were interviewed about their sexual partners and practices over the last 12 months during which it emerged that they had had a total of 360 sexual partners. Multiple linear regression analyses were performed to identify factors related to SRB in 222 main (spouse, mistress and girlfriend) and 138 casual partners (colleague, friend, casual encounter and sex worker). Results showed a significantly higher SRB score with casual partners. For the main partner regression model, prior exposure to HIV- and STD-preventive information and sexual intercourse with higher employment status partners (formal workers vs. self-employed in informal activities and unemployed) were associated with lower SRB scores, but if the sexual relations occurred in Mexico (vs. the U.S.), the SRB scores increased. For the casual partner model, the practice of survival sex (sex in exchange for basic needs), sexual relations in Mexico (vs. the U.S.), and being a circular migrant (person traveling for temporary work to return home when the contract is over) were related to higher SRB scores. Findings support the implementation of preventive interventions using different messages depending on the type of partners, main or casual, within the labor migrant context.
-
Revictimization of Victims Sexually Abused by Women
Directory of Open Access Journals (Sweden)
Małgorzata H. Kowalczyk
2017-07-01
Full Text Available Victims experiencing the sexual abuse are surviving not only physical injustice but above all deep traumas, which very often in different forms, are keeping them company through the entire life. Quite often at establishing different results a sex is underestimated for the perpetrator. Therefore knowing the problem of sexual abuses from a perspective of close as well as distant results is very important in the event that a woman was a perpetrator of these acts – mother, minder. In the present article based on analysis of literature, a problem of results of the sexual abuse was presented at victims which experienced these behaviours on the part of women. In order to draw up discussing the survived specificity by victims was both of sex of the trauma connected with the sexual application as well as close and distant consequences of these events in the form prime victimisation and revictimisation for figure being noticeable in the adult life of psychosexual disorders and social shortages. Amongst the consequence isolated traumatic factors are deserving the particular attention about dynamic character which are provoking the appearance of many symptoms characteristic of children which experienced the sexual violence. Recalled factors it: traumatic sexualisation of child, the betrayal, the stigmatization and the helplessness. The specificity of these factors results from the fact that they will leave distant “tracks” in the psyche and they can undergo the additional reinforcement if a woman is a perpetrator of the sexual violence. It results from frequent attitudes of “denying” towards the sexual violence applied by women. In the study they pointed also at one of possible consequences of the revictimisation process copying patterns of behaviour connected with the sexual exploitation of children in their more late life by victims is which. This process resulting from the alternating identification of the perpetrator and the victim is starting
-
Connallon, Tim; Clark, Andrew G
2010-12-01
Sex-biased genes--genes that are differentially expressed within males and females--are nonrandomly distributed across animal genomes, with sex chromosomes and autosomes often carrying markedly different concentrations of male- and female-biased genes. These linkage patterns are often gene- and lineage-dependent, differing between functional genetic categories and between species. Although sex-specific selection is often hypothesized to shape the evolution of sex-linked and autosomal gene content, population genetics theory has yet to account for many of the gene- and lineage-specific idiosyncrasies emerging from the empirical literature. With the goal of improving the connection between evolutionary theory and a rapidly growing body of genome-wide empirical studies, we extend previous population genetics theory of sex-specific selection by developing and analyzing a biologically informed model that incorporates sex linkage, pleiotropy, recombination, and epistasis, factors that are likely to vary between genes and between species. Our results demonstrate that sex-specific selection and sex-specific recombination rates can generate, and are compatible with, the gene- and species-specific linkage patterns reported in the genomics literature. The theory suggests that sexual selection may strongly influence the architectures of animal genomes, as well as the chromosomal distribution of fixed substitutions underlying sexually dimorphic traits. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.
-
Sexual imprinting on ecologically divergent traits leads to sexual isolation in sticklebacks.
Kozak, Genevieve M; Head, Megan L; Boughman, Janette W
2011-09-07
During sexual imprinting, offspring learn parental phenotypes and then select mates who are similar to their parents. Imprinting has been thought to contribute to the process of speciation in only a few rare cases; this is despite imprinting's potential to generate assortative mating and solve the problem of recombination in ecological speciation. If offspring imprint on parental traits under divergent selection, these traits will then be involved in both adaptation and mate preference. Such 'magic traits' easily generate sexual isolation and facilitate speciation. In this study, we show that imprinting occurs in two ecologically divergent stickleback species (benthics and limnetics: Gasterosteus spp.). Cross-fostered females preferred mates of their foster father's species. Furthermore, imprinting is essential for sexual isolation between species; isolation was reduced when females were raised without fathers. Daughters imprinted on father odour and colour during a critical period early in development. These traits have diverged between the species owing to differences in ecology. Therefore, we provide the first evidence that imprinting links ecological adaptation to sexual isolation between species. Our results suggest that imprinting may facilitate the evolution of sexual isolation during ecological speciation, may be especially important in cases of rapid diversification, and thus play an integral role in the generation of biodiversity.
-
Sexual selection as a consequence of pathogen avoidance behaviors
Energy Technology Data Exchange (ETDEWEB)
Loehle, C. [Argonne National Lab., IL (United States); Logofet, D.O. [Russian Academy of Sciences, Moscow (Russian Federation). Laboratory of Mathematical Ecology
1997-08-01
The current theory that sexual selection results from female choice for good genes suffers from several problems. An alternative explanation is proposed. The pathogen avoidance hypothesis argues that the primary function of showy traits is to provide a reliable signal of current disease status so that sick individuals may be avoided during mating. Our studies shown that a significant risk of pathogen transmission occurs during mating and that showy traits are reliable indicators of current disease status. The origin of female choosiness is argued to lie in a general tendency to avoid sick individuals, even in the absence of showy traits. The showy traits are argued to originate as simple exaggerations of normal traits that are indicative of good health (bright feathers; vigorous movement; large size). Thus the origins of both showy traits and female choosiness are not problematic in this theory. A game theory analysis is employed to formalize the theory. Results of the game theory model support the theory. In particular, when the possession of male showy traits does not help reduce disease in the female, then showy traits are unlikely to occur. This case corresponds to the situation in large flocks or herds in which every animal is thoroughly exposed to all group pathogens on average. Such species do not exhibit showy traits. The good genes model does not make this prediction. The pathogen avoidance model can also lead to the evolution of showy traits even when selection is not effective against a given pathogen (e.g., when there is no heritable variation for resistance) but will lead to selection for resistance if such genes are present. Overall, the pathogen avoidance hypothesis provides a complete alternative to the good genes theory.
-
SEXUAL SELECTION. Irrationality in mate choice revealed by túngara frogs.
Lea, Amanda M; Ryan, Michael J
2015-08-28
Mate choice models derive from traditional microeconomic decision theory and assume that individuals maximize their Darwinian fitness by making economically rational decisions. Rational choices exhibit regularity, whereby the relative strength of preferences between options remains stable when additional options are presented. We tested female frogs with three simulated males who differed in relative call attractiveness and call rate. In binary choice tests, females' preferences favored stimulus caller B over caller A; however, with the addition of an inferior "decoy" C, females reversed their preferences and chose A over B. These results show that the relative valuation of mates is not independent of inferior alternatives in the choice set and therefore cannot be explained with the rational choice models currently used in sexual selection theory. Copyright © 2015, American Association for the Advancement of Science.
-
Queen Specific Exocrine Glands in Legionary Ants and Their Possible Function in Sexual Selection.
Hölldobler, Bert
2016-01-01
The colonies of army ants and some other legionary ant species have single, permanently wingless queens with massive post petioles and large gasters. Such highly modified queens are called dichthadiigynes. This paper presents the unusually rich exocrine gland endowment of dichthadiigynes, which is not found in queens of other ant species. It has been suggested these kinds of glands produce secretions that attract and maintain worker retinues around queens, especially during migration. However, large worker retinues also occur in non-legionary species whose queens do not have such an exuberance of exocrine glands. We argue and present evidence in support of our previously proposed hypothesis that the enormous outfit of exocrine glands found in dichthadiigynes is due to sexual selection mediated by workers as the main selecting agents.
-
Queen Specific Exocrine Glands in Legionary Ants and Their Possible Function in Sexual Selection.
Directory of Open Access Journals (Sweden)
Bert Hölldobler
Full Text Available The colonies of army ants and some other legionary ant species have single, permanently wingless queens with massive post petioles and large gasters. Such highly modified queens are called dichthadiigynes. This paper presents the unusually rich exocrine gland endowment of dichthadiigynes, which is not found in queens of other ant species. It has been suggested these kinds of glands produce secretions that attract and maintain worker retinues around queens, especially during migration. However, large worker retinues also occur in non-legionary species whose queens do not have such an exuberance of exocrine glands. We argue and present evidence in support of our previously proposed hypothesis that the enormous outfit of exocrine glands found in dichthadiigynes is due to sexual selection mediated by workers as the main selecting agents.
-
Woolf-King, Sarah E.; Maisto, Stephen; Carey, Michael; Vanable, Peter
2013-01-01
Experimental research on sexual decision making is limited, despite the public health importance of such work. We describe formative work conducted in advance of an experimental study designed to evaluate the effects of alcohol intoxication and sexual arousal on risky sexual decision making among men who have sex with men. In Study 1, we describe the procedures for selecting and validating erotic film clips (to be used for the experimental manipulation of arousal). In Study 2, we describe the tailoring of two interactive role-play videos to be used to measure risk perception and communication skills in an analog risky sex situation. Together, these studies illustrate a method for creating experimental stimuli to investigate sexual decision making in a laboratory setting. Research using this approach will support experimental research that affords a stronger basis for drawing causal inferences regarding sexual decision making. PMID:19760530
-
An Approach to Addressing Selection Bias in Survival Analysis
Carlin, Caroline S.; Solid, Craig A.
2014-01-01
This work proposes a frailty model that accounts for non-random treatment assignment in survival analysis. Using Monte Carlo simulation, we found that estimated treatment parameters from our proposed endogenous selection survival model (esSurv) closely parallel the consistent two-stage residual inclusion (2SRI) results, while offering computational and interpretive advantages. The esSurv method greatly enhances computational speed relative to 2SRI by eliminating the need for bootstrapped standard errors, and generally results in smaller standard errors than those estimated by 2SRI. In addition, esSurv explicitly estimates the correlation of unobservable factors contributing to both treatment assignment and the outcome of interest, providing an interpretive advantage over the residual parameter estimate in the 2SRI method. Comparisons with commonly used propensity score methods and with a model that does not account for non-random treatment assignment show clear bias in these methods that is not mitigated by increased sample size. We illustrate using actual dialysis patient data comparing mortality of patients with mature arteriovenous grafts for venous access to mortality of patients with grafts placed but not yet ready for use at the initiation of dialysis. We find strong evidence of endogeneity (with estimate of correlation in unobserved factors ρ̂ = 0.55), and estimate a mature-graft hazard ratio of 0.197 in our proposed method, with a similar 0.173 hazard ratio using 2SRI. The 0.630 hazard ratio from a frailty model without a correction for the non-random nature of treatment assignment illustrates the importance of accounting for endogeneity. PMID:24845211
-
Coming of age on the streets: survival sex among homeless young women in Hollywood.
Warf, Curren W; Clark, Leslie F; Desai, Mona; Rabinovitz, Susan J; Agahi, Golnaz; Calvo, Richard; Hoffmann, Jenny
2013-12-01
This study examined childhood physical or sexual abuse, involvement in dependency or delinquency systems, psychiatric hospitalization, and suicide as possible risk factors for survival sex among homeless young women. Homeless young women were found to have similarly high rates of childhood sexual abuse, dependency and delinquency systems involvement, and psychiatric hospitalization. Homeless young women involved in survival sex disclosed higher rates of attempted suicide and reported marginally higher rates of childhood physical abuse. Analysis of qualitative data showed that those engaged in survival sex were motivated primarily by desperation to meet basic needs including a place to stay, food and money, and one third mentioned that peers commonly were influential in decisions to engage in survival sex. Others were influenced by coercion (10%) or pursuit of drugs (10%). Young women engaged in survival sex generally experienced regret and shame about their experience. Copyright © 2013 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.
-
Limmer, Mark
2016-03-01
Understanding and addressing the sexual risk taking of young men remains a key research, policy, and practice concern in attempts to improve the emotional and physical sexual health of young men and their sexual partners. This article explores one of the ways in which young men attempt to mitigate sexual risk through the assigning of labels to particular young women and using these as a basis for their decisions in relation to sexual activity, contraception, and condom use. The article uses the lens of hegemonic masculinities theory to increase understanding of the role played by the construction and performance of marginalized masculinities and how these in turn are influenced by social exclusionary processes. The article draws on focus group and interview data from 46 young men aged 15 to 17 years living in the northwest of England, purposively selected on the basis of the prevailing policy definitions of social inclusion and exclusion. The article describes a form of marginalized masculinity pertaining to socially excluded young men, which as a result of limited access to other tenets of hegemonic masculinity, is disproportionately reliant on sexual expertise and voracity alongside overt demonstrations of their superiority over women. It is in this context that young women are assigned the labels of "dirty" or "clean" on the basis of a selection of arbitrary judgments relating to dress, demeanor, area of residence, and perceived sexual activities. The motivations of the young men, the impact on young women, and the policy and practice implications are all discussed. © The Author(s) 2014.
-
Taylor, Tonya N; Munoz-Plaza, Corrine E; Goparaju, Lakshmi; Martinez, Omar; Holman, Susan; Minkoff, Howard L; Karpiak, Stephen E; Gandhi, Monica; Cohen, Mardge H; Golub, Elizabeth T; Levine, Alexandra M; Adedimeji, Adebola A; Gonsalves, Rebecca; Bryan, Tiffany; Connors, Nina; Schechter, Gabrielle; Wilson, Tracey E
2017-05-01
There is limited research examining the sexual health and well-being of older women living with HIV (OWLH). Most studies focus on sexual dysfunction, leaving aside the richer context of sexuality and sexual health, including the effect of age-related psychosocial and interpersonal changes on sexual health behaviors. Guided by the integrative biopsychosocial model and the sexual health model, this study explored the importance of sex and sexuality among OWLH to identify their sexual health and HIV prevention needs for program planning. A purposive sample (n = 50) of OWLH was selected from a parent study (n = 2052). We conducted 8 focus groups and 41 in-depth interviews with 50 African American and Latina OWLH aged 50-69 years old in three U.S. cities. The triangulation approach was used to synthesize the data. Six salient themes emerged: sexual pleasure changes due to age, sexual freedom as women age, the role of relationships in sexual pleasure, changes in sexual ability and sexual health needs, sexual risk behaviors, and ageist assumptions about older women's sexuality. We found that sexual pleasure and the need for intimacy continue to be important for OWLH, but that changing sexual abilities and sexual health needs, such as the reduction of sexual desire, as well as increased painful intercourse due to menopause-associated vaginal drying, were persistent barriers to sexual fulfillment and satisfaction. Particular interpersonal dynamics, including low perceptions of the risk of HIV transmission as related to gender, viral suppression, and habitual condomless sex with long-term partners without HIV transmission have resulted in abandoning safer sex practices with serodiscordant partners. These findings suggest that HIV prevention for OWLH should focus on how sexual function and satisfaction intersect with sexual risk. HIV prevention for OWLH should promote ways to maintain satisfying and safe sex lives among aging women.
-
A cost of sexual attractiveness to high-fitness females.
Directory of Open Access Journals (Sweden)
Tristan A F Long
2009-12-01
Full Text Available Adaptive mate choice by females is an important component of sexual selection in many species. The evolutionary consequences of male mate preferences, however, have received relatively little study, especially in the context of sexual conflict, where males often harm their mates. Here, we describe a new and counterintuitive cost of sexual selection in species with both male mate preference and sexual conflict via antagonistic male persistence: male mate choice for high-fecundity females leads to a diminished rate of adaptive evolution by reducing the advantage to females of expressing beneficial genetic variation. We then use a Drosophila melanogaster model system to experimentally test the key prediction of this theoretical cost: that antagonistic male persistence is directed toward, and harms, intrinsically higher-fitness females more than it does intrinsically lower-fitness females. This asymmetry in male persistence causes the tails of the population's fitness distribution to regress towards the mean, thereby reducing the efficacy of natural selection. We conclude that adaptive male mate choice can lead to an important, yet unappreciated, cost of sex and sexual selection.
-
Modeling Sexual Selection in Túngara Frog and Rationality of Mate Choice.
Vargas Bernal, Esteban; Sanabria Malagon, Camilo
2017-12-01
The males of the species of frogs Engystomops pustulosus produce simple and complex calls to lure females, as a way of intersexual selection. Complex calls lead males to a greater reproductive success than what simple calls do. However, the complex calls are also more attractive to their main predator, the bat Trachops cirrhosus. Therefore, as M. Ryan suggests in (The túngara frog: a study in sexual selection and communication. University of Chicago Press, Chicago, 1985), the complexity of the calls lets the frogs keep a trade-off between reproductive success and predation. In this paper, we verify this trade-off from the perspective of game theory. We first model the proportion of simple calls as a symmetric game of two strategies. We also model the effect of adding a third strategy, males that keep quiet and intercept females, which would play a role of intrasexual selection. Under the assumption that the decision of the males takes into account this trade-off between reproductive success and predation, our model reproduces the observed behavior reported in the literature with minimal assumption on the parameters. From the model with three strategies, we verify that the quiet strategy could only coexists with the simple and complex strategies if the rate at which quiet males intercept females is high, which explains the rarity of the quiet strategy. We conclude that the reproductive strategy of the male frog E. pustulosus is rational.
-
Choularia, Zoe; Hutchison, Craig; Karatzias, Thanos
2009-01-01
Primary objective: The authors sought to summarise and evaluate evidence regarding vicarious traumatisation (VT) in practitioners working with adult survivors of sexual violence and/or child sexual abuse (CSA). Methods and selection criteria: Relevant publications were identified from systematic literature searches of PubMed and PsycINFO. Studies were selected for inclusion if they examined vicarious traumatisation resulting from sexual violence and/or CSA work and were published in English b...
-
Young, Michael; Palacios, Rebecca; Penhollow, Tina M.
2012-01-01
To improve the quality of research and commentary concerning adolescent sexuality and evaluation of both comprehensive sexuality education and abstinence education programs, this article aims to help readers (1) select appropriate measures to study adolescent sexual behavior, (2) develop appropriate study designs to evaluate adolescent sexual…
-
Freshman Sexual Attitudes and Behavior.
Nutt, Roberta L.; Sedlacek, William E.
At the University of Maryland, 758 randomly selected incoming freshman students were administered an anonymous poll regarding their sexual attitudes and behavior. Results showed that the Maryland freshman generally resembled other U.S. college students in their sexual experience. Approximately half (52% of males, 46% of females) reported that they…
-
Taylor, Tonya N.; Munoz-Plaza, Corrine E.; Goparaju, Lakshmi; Martinez, Omar; Holman, Susan; Minkoff, Howard L.; Karpiak, Stephen E.; Gandhi, Monica; Cohen, Mardge H.; Golub, Elizabeth T.; Levine, Alexandra M.; Adedimeji, Adebola A.; Gonsalves, Rebecca; Bryan, Tiffany; Connors, Nina; Schechter, Gabrielle; Wilson, Tracey E.
2016-01-01
There is limited research examining the sexual health and wellbeing of older women living with HIV (OWLH). Most studies focus on sexual dysfunction, leaving aside the richer context of sexuality and sexual health, including the effect of age-related psychosocial and interpersonal changes on sexual health behaviors. Guided by the integrative biopsychosocial model and the sexual health model, this study explored the importance of sex and sexuality among OWLH to identify their sexual health and HIV prevention needs for program planning. A purposive sample (n=50) of OWLH was selected from a parent study (n=2,052). We conducted 8 focus groups and 41 in-depth interviews with 50 African American and Latina OWLH aged 50–69 years old in three U.S. cities. The triangulation approach was used to synthesize the data. Six salient themes emerged: sexual pleasure changes due to age, sexual freedom as women age, the role of relationships in sexual pleasure, changes in sexual ability and sexual health needs, sexual risk behaviors, and ageist assumptions about older women’s sexuality. We found that sexual pleasure and the need for intimacy continue to be important for OWLH, but that changing sexual abilities and sexual health needs, such as the reduction of sexual desire, as well as increased painful intercourse due to menopause-associated vaginal drying, were persistent barriers to sexual fulfillment and satisfaction. Particular interpersonal dynamics, including low perceptions of the risk of HIV transmission as related to gender, viral suppression and habitual condomless sex with long term partners without HIV transmission have resulted in abandoning safer sex practices with serodiscordant partners. These findings suggest that HIV prevention for OWLH should focus on how sexual function and satisfaction intersect with sexual risk. HIV prevention for OWLH should promote ways to maintain satisfying and safe sex lives among aging women. PMID:27220311
-
Directory of Open Access Journals (Sweden)
Amiteye Samuel
2011-08-01
Full Text Available Abstract Background Apomixis, a natural form of asexual seed production in plants, is considered to have great biotechnological potential for agriculture. It has been hypothesised that de-regulation of the sexual developmental pathway could trigger apomictic reproduction. The genus Boechera represents an interesting model system for understanding apomixis, having both sexual and apomictic genotypes at the diploid level. Quantitative qRT-PCR is the most extensively used method for validating genome-wide gene expression analyses, but in order to obtain reliable results, suitable reference genes are necessary. In this work we have evaluated six potential reference genes isolated from a 454 (FLX derived cDNA library of Boechera. RNA from live microdissected ovules and anthers at different developmental stages, as well as vegetative tissues of apomictic and sexual Boechera, were used to validate the candidates. Results Based on homologies with Arabidopsis, six genes were selected from a 454 cDNA library of Boechera: RPS18 (Ribosomal sub protein 18, Efalpha1 (Elongation factor 1 alpha, ACT 2 (Actin2, UBQ (polyubiquitin, PEX4 (Peroxisomal ubiquitin conjugating enzyme and At1g09770.1 (Arabidopsis thaliana cell division cycle 5. Total RNA was extracted from 17 different tissues, qRT-PCRs were performed, and raw Ct values were analyzed for primer efficiencies and gene ratios. The geNorm and normFinder applications were used for selecting the most stable genes among all tissues and specific tissue groups (ovule, anthers and vegetative tissues in both apomictic and sexual plants separately. Our results show that BoechRPS18, BoechEfα1, BoechACT2 and BoechUBQ were the most stable genes. Based on geNorm, the combinations of BoechRPS18 and BoechEfα1 or BoechUBQ and BoechEfα1 were the most stable in the apomictic plant, while BoechRPS18 and BoechACT2 or BoechUBQ and BoechACT2 performed best in the sexual plant. When subgroups of tissue samples were analyzed
-
Thoa, Ngo Phu; Ninh, Nguyen Huu; Knibb, Wayne; Nguyen, Nguyen Hong
2016-02-19
This study assessed whether selection for high growth in a challenging environment of medium salinity produces tilapia genotypes that perform well across different production environments. We estimated the genetic correlations between trait expressions in saline and freshwater using a strain of Nile tilapia selected for fast growth under salinity water of 15-20 ppt. We also estimated the heritability and genetic correlations for new traits of commercial importance (sexual maturity, feed conversion ratio, deformity and gill condition) in a full pedigree comprising 36,145 fish. The genetic correlations for the novel characters between the two environments were 0.78-0.99, suggesting that the effect of genotype by environment interaction was not biologically important. Across the environments, the heritability for body weight was moderate to high (0.32-0.62), indicating that this population will continue responding to future selection. The estimates of heritability for sexual maturity and survival were low but significant. The additive genetic components also exist for FCR, gill condition and deformity. Genetic correlations of harvest body weight with sexual maturity were positive and those between harvest body weight with FCR were negative. Our results indicate that the genetic line selected under a moderate saline water environment can be cultured successfully in freshwater systems.
-
Phase Transitions in Sexual Populations Subject to Stabilizing Selection
Rogers, A.
2003-04-01
We show that a simple model of an evolving sexual population, which dates back to some of the earliest work in theoretical population genetics, exhibits an unexpected and previously unobserved phase transition between ordered and disordered states. This behavior is not present in populations evolving asexually without recombination and is thus important in any comparison of sexual and asexual populations. In order to calculate the details of the phase transition, we use techniques from statistical physics. We introduce the correlation of the population as the order parameter of the system and use maximum entropy inference to find the state of the population at any time.
-
Fishery-induced selection for slow somatic growth in European eel.
Directory of Open Access Journals (Sweden)
Daniele Bevacqua
Full Text Available Both theoretical and experimental studies have shown that fishing mortality can induce adaptive responses in body growth rates of fishes in the opposite direction of natural selection. We compared body growth rates in European eel (Anguilla anguilla from three Mediterranean stocks subject to different fishing pressure. Results are consistent with the hypotheses that i fast-growing individuals are more likely to survive until sexual maturity than slow-growing ones under natural conditions (no fishing and ii fishing can select for slow-growing individuals by removing fast-growing ones. Although the possibility of human-induced evolution seems remote for a panmictic species like such as the European eel, further research is desirable to assess the implications of the intensive exploitation on this critically endangered fish.
-
Cryptic sexual size dimorphism in Malagasy plovers Charadrius spp ...
African Journals Online (AJOL)
Taken together, our work reports SSD in small African plovers that exhibit monomorphic plumage, and we propose that SSD may be more common than currently acknowledged; we term this 'cryptic sexual size dimorphism'. Our results also suggest sexual selection and/or natural selection exert different pressures on body ...
-
Sexual safety and sexual security among young Black women who have sex with women and men.
Alexander, Kamila Anise; Fannin, Ehriel F
2014-01-01
To examine sexuality narratives of Black women who have sex with women and men and explore factors that influence their sexual safety and sexual security. Secondary qualitative content analysis. We recruited young self-identified Black women from beauty salons and community-based organizations. Our sample included a subset of five sexually active, Black women age 19 to 25 who reported engaging in sexual relationships with women and men. Participants were selected from a larger parent study that included sexuality narratives from 25 women. We analyzed interview transcripts in which participants described sexual relationships. We used constant comparative techniques and conventional content analysis methodology. We uncovered three themes illustrating influences on sexual safety and sexual security: institutional expectations, emotional connectedness, and sexual behaviors. From this analysis, we derive valuable insights into decision-making processes within sexual relationships from the perspectives of young Black women who have sex with women and men. Clinicians and investigators can use these findings to inform programs designed to improve the sexual health of this often invisible group of women. Nurses are uniquely positioned to support young women as they navigate societal institutions and emotional experiences that inform future sexual decisions and behaviors. © 2014 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.
-
Senior Adult Sexuality in Age Segregated and Age Integrated Communities.
Weinstein, Stellye; Rosen, Efrem
1988-01-01
Middle-income older adults (N=314) responded to senior adult sexuality scale. Results showed that respondents who selected to reside in age-segregated leisure-type retirement communities exhibited significantly more sexual interest, sexual activities, and liberal sexual attitudes than did respondents residing in age-integrated mainstream…
-
Trilobite spines and beetle horns: sexual selection in the Palaeozoic?
Knell, Robert J; Fortey, Richard A
2005-06-22
Raphiophorid trilobites commonly bore median cephalic protuberances such as spines or bulbs, showing a remarkable variety of form. It is unlikely that their primary function was for protection or in hydrodynamics. A case is made that they were secondary sexual features, by comparison with similar morphological structures developed on rhinoceros beetles and other arthropods. This interpretation is supported by four lines of evidence: their ontogeny, their diversity, the existence of plausible examples of sexual dimorphs in some cases and the fact that they show positive allometry.
-
Exposure to sexualized media content and selective attention for sexual cues: An experimental study
Doornwaard, Suzan; van den Eijnden, Regina; Johnson, Adam; ter Bogt, Tom
2014-01-01
This study examined whether exposure to sexualized media influences the subconscious process of attention allocation to subsequently encountered stimuli. One hundred twenty-three participants (61 females) between 18-23 years (M age = 19.99 years) watched a 3-minute video clip containing either
-
Evidence for strong intralocus sexual conflict in the Indian meal moth, Plodia interpunctella.
Lewis, Zenobia; Wedell, Nina; Hunt, John
2011-07-01
Males and females share a genome and express many shared phenotypic traits, which are often selected in opposite directions. This generates intralocus sexual conflict that may constrain trait evolution by preventing the sexes from reaching their optimal phenotype. Furthermore, if present across multiple loci, intralocus sexual conflict can result in a gender load that may diminish the benefits of sexual selection and help maintain genetic variation for fitness. Despite the importance of intralocus sexual conflict, surprisingly few empirical studies conclusively demonstrate its operation. We show that the pattern of multivariate selection acting on three sexually dimorphic life-history traits (development time, body size, and longevity) in the Indian meal moth, Plodia interpunctella, is opposing for the sexes. Moreover, we combined our estimates of selection with the additive genetic variance-covariance matrix (G) to predict the evolutionary response of the life-history traits in the sexes and showed that the angle between the vector of responses and the vector of sexually antagonistic selection was almost orthogonal at 84.70°. Thus, G biases the predicted response of life-history traits in the sexes away from the direction of sexually antagonistic selection, confirming the presence of strong intralocus sexual conflict in this species. Despite this, sexual dimorphism has evolved in all of the life-history traits examined suggesting that mechanism(s) have evolved to resolve this conflict and allow the sexes to reach their life-history optima. We argue that intralocus sexual conflict is likely to play an important role in the evolution of divergent life-history strategies between the sexes in this species. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
-
Crothers, Laura R; Cummings, Molly E
2013-05-01
Though theory predicts consistency of warning signals in aposematic species to facilitate predator learning, variation in these signals often occurs in nature. The strawberry poison frog Dendrobates pumilio is an exceptionally polytypic (populations are phenotypically distinct) aposematic frog exhibiting variation in warning color and brightness. In the Solarte population, males and females both respond differentially to male brightness variation. Here, we demonstrate through spectrophotometry and visual modeling that aposematic brightness variation within this population is likely visible to two putative predators (crabs, snakes) and conspecifics but not to the presumed major predator (birds). This study thus suggests that signal brightness within D. pumilio populations can be shaped by sexual selection, with limited opportunity for natural selection to influence this trait due to predator sensory constraints. Because signal brightness changes can ultimately lead to changes in hue, our findings at the within-population level can provide insights into understanding this polytypism at across-population scales.
-
DEFF Research Database (Denmark)
Andersen, Anders Holst; Korsgaard, Inge Riis; Jensen, Just
2002-01-01
In this paper, we consider selection based on the best predictor of animal additive genetic values in Gaussian linear mixed models, threshold models, Poisson mixed models, and log normal frailty models for survival data (including models with time-dependent covariates with associated fixed...... or random effects). In the different models, expressions are given (when these can be found - otherwise unbiased estimates are given) for prediction error variance, accuracy of selection and expected response to selection on the additive genetic scale and on the observed scale. The expressions given for non...... Gaussian traits are generalisations of the well-known formulas for Gaussian traits - and reflect, for Poisson mixed models and frailty models for survival data, the hierarchal structure of the models. In general the ratio of the additive genetic variance to the total variance in the Gaussian part...
-
Selective histone deacetylase 6 inhibition prolongs survival in a lethal two-hit model.
Cheng, Xin; Liu, Zhengcai; Liu, Baoling; Zhao, Ting; Li, Yongqing; Alam, Hasan B
2015-07-01
Hemorrhagic shock (HS) followed by a subsequent insult ("second hit") often initiates an exaggerated systemic inflammatory response and multiple organ failure. We have previously demonstrated that valproic acid, a pan histone deacetylase inhibitor, could improve survival in a rodent "two-hit" model. In the present study, our goal was to determine whether selective inhibition of histone deacetylase 6 with Tubastatin A (Tub-A) could prolong survival in a two-hit model where HS was followed by sepsis from cecal ligation and puncture (CLP). C57Bl/6J mice were subjected to sublethal HS (30% blood loss) and then randomly divided into two groups (n = 13 per group) such as Tub-A group (treatment) and vehicle (VEH) group (control). The Tub-A group was given an intraperitoneal injection of Tub-A (70 mg/kg) dissolved in dimethyl sulfoxide (DMSO). The VEH group was injected with DMSO (1 μl/g body weight). After 24 h, all mice were subjected CLP followed immediately by another dose of Tub-A or DMSO. Survival was monitored for 10 d. In a parallel study, peritoneal irrigation fluid and liver tissue from Tub-A- or DMSO-treated mice were collected 3 h after CLP. Enzyme-linked immunosorbent assay was performed to quantify activity of the myeloperoxidase and concentrations of tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) in the peritoneal irrigation fluid. RNA was isolated from the liver tissue, and real-time polymerase chain reaction was performed to measure relative messenger RNA levels of TNF-α and IL-6. Treatment with Tub-A significantly improved survival compared with that of the control (69.2% versus 15.4%). In addition, Tub-A significantly suppressed myeloperoxidase activity (169.9 ± 8.4 ng/mL versus 70.4 ± 17.4 ng/mL; P hit model. Copyright © 2015 Elsevier Inc. All rights reserved.
-
SURVIVING SEXUAL ABUSE IN EVERYDAY LIFE: FORMS OF RESISTANCE USED BY CHILDREN AND ADOLESCENTS
Directory of Open Access Journals (Sweden)
Margaret Olinda de Souza Carvalho e Lira
2017-01-01
Full Text Available Objetivo: aprender formas de resistencia utilizadas por niños y adolescentes en un cotidiano familiar de abuso sexual. Método: investigación cualitativa desarrollada en un Centro de Atendimiento a la Mujer en Situación de Violencia en el Semiárido de Pernambuco, con datos recolectados entre junio y noviembre de 2014, por medio de entrevista con nueve mujeres. El proceso de análisis se fundamentó en nociones de la Sociología Comprensiva y del Cotidiano, con datos organizados por afinidad, interpretados y categorizados. Resultados: emergieron las categorías: ritualización del abuso sexual de niños y adolescentes en el cotidiano familiar: aceptación de la vida por la pasividad; camuflajes para sobrevivir a lo vivido sobre el abuso sexual: silencio, astucia y doble juego, y, entre lo oculto y la revelación del abuso sexual. Puede percibirse que los episodios de abuso ocurrían en secreto y bajo la amenaza de los abusadores a través de gestos o palabras intimidantes. Las víctimas no entraban en confrontación con ellos y para llamar la atención o pedir auxilio usaban artimañas como metáforas, risas y palabras irónicas, además de despistarlos con disculpas, escondiéndose, fingiendo dormir o escapándose para la calle. Conclusión: la centralidad subterránea presente en el abuso sexual desencadenó formas de resistencia en oposición a la opresión generada por el abusador en que, para la aceptación de la vida, las participantes desarrollaron diferentes mecanismos de sobrevivencia, además de encontrar en el trabajo voluntario, música y deporte, los respiraderos para aliviar el peso generado por la ocultación del abuso.
-
Sexual orientation data collection and progress toward Healthy People 2010.
Sell, R L; Becker, J B
2001-06-01
Without scientifically obtained data and published reports, it is difficult to raise awareness and acquire adequate resources to address the health concerns of lesbian, gay, and bisexual Americans. The Department of Health and Human Services must recognize gaps in its information systems regarding sexual orientation data and take immediate steps to monitor and eliminate health disparities as delineated in Healthy People 2010. A paper supported by funding from the Office of the Assistant Secretary for Planning and Evaluation explores these concerns and suggests that the department (1) create work groups to examine the collection of sexual orientation data; (2) create a set of guiding principles to govern the process of selecting standard definitions and measures; (3) recognize that racial/ethnic, immigrant-status, age, socioeconomic, and geographic differences must be taken into account when standard measures of sexual orientation are selected; (4) select a minimum set of standard sexual orientation measures; and (5) develop a long-range strategic plan for the collection of sexual orientation data.
-
High male sexual investment as a driver of extinction in fossil ostracods.
Martins, Maria João Fernandes; Puckett, T Markham; Lockwood, Rowan; Swaddle, John P; Hunt, Gene
2018-04-01
Sexual selection favours traits that confer advantages in the competition for mates. In many cases, such traits are costly to produce and maintain, because the costs help to enforce the honesty of these signals and cues 1 . Some evolutionary models predict that sexual selection also produces costs at the population level, which could limit the ability of populations to adapt to changing conditions and thus increase the risk of extinction 2-4 . Other models, however, suggest that sexual selection should increase rates of adaptation and enhance the removal of deleterious mutations, thus protecting populations against extinction 3, 5, 6 . Resolving the conflict between these models is not only important for explaining the history of biodiversity, but also relevant to understanding the mechanisms of the current biodiversity crisis. Previous attempts to test the conflicting predictions produced by these models have been limited to extant species and have thus relied on indirect proxies for species extinction. Here we use the informative fossil record of cytheroid ostracods-small, bivalved crustaceans with sexually dimorphic carapaces-to test how sexual selection relates to actual species extinction. We show that species with more pronounced sexual dimorphism, indicating the highest levels of male investment in reproduction, had estimated extinction rates that were ten times higher than those of the species with the lowest investment. These results indicate that sexual selection can be a substantial risk factor for extinction.
-
Kawatsu, Kazutaka
2013-02-01
The assumption of a twofold cost of sex not only complicates the maintenance of sex but also sets conditions for sexual conflict: in organisms with the twofold cost, males often sexually harass females. Sexual harassment is detrimental to female fitness and thus might help maintain sexual populations if male harassment inflicts a harsher cost on parthenogens than on sexual females (asymmetric harassment cost). However, the generality of this concept is now considered doubtful because selective harassment of parthenogens results in loss of mating opportunities for males. Using three mathematical models, I show here that sexual harassment still can impose the asymmetric cost on parthenogens. First, I apply the Lotka-Volterra model to show the degree of asymmetric harassment cost that permits sex to be maintained stably in the population. Second, using adaptive dynamics, I examine whether sexually antagonistic coevolution for sexual harassment, which occurs only in sexual populations, can promote the asymmetric harassment cost. Finally, an individual-based model, which assumes a spatial structure unlike that in the other two, demonstrates that the asymmetric evolution of harassment cost prevents further invasions of parthenogens from different patches into sexual lineages; these mechanisms may account for allopatric distributions of sexual and parthenogenetic lineages as well as the maintenance of sex.
-
Directory of Open Access Journals (Sweden)
Damien C Tully
2016-05-01
Full Text Available Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU, we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic "signatures" within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission.
-
Sexual dimorphism in bite performance drives morphological variation in chameleons.
da Silva, Jessica M; Herrel, Anthony; Measey, G John; Tolley, Krystal A
2014-01-01
Phenotypic performance in different environments is central to understanding the evolutionary and ecological processes that drive adaptive divergence and, ultimately, speciation. Because habitat structure can affect an animal's foraging behaviour, anti-predator defences, and communication behaviour, it can influence both natural and sexual selection pressures. These selective pressures, in turn, act upon morphological traits to maximize an animal's performance. For performance traits involved in both social and ecological activities, such as bite force, natural and sexual selection often interact in complex ways, providing an opportunity to understand the adaptive significance of morphological variation with respect to habitat. Dwarf chameleons within the Bradypodion melanocephalum-Bradypodion thamnobates species complex have multiple phenotypic forms, each with a specific head morphology that could reflect its use of either open- or closed-canopy habitats. To determine whether these morphological differences represent adaptations to their habitats, we tested for differences in both absolute and relative bite performance. Only absolute differences were found between forms, with the closed-canopy forms biting harder than their open-canopy counterparts. In contrast, sexual dimorphism was found for both absolute and relative bite force, but the relative differences were limited to the closed-canopy forms. These results indicate that both natural and sexual selection are acting within both habitat types, but to varying degrees. Sexual selection seems to be the predominant force within the closed-canopy habitats, which are more protected from aerial predators, enabling chameleons to invest more in ornamentation for communication. In contrast, natural selection is likely to be the predominant force in the open-canopy habitats, inhibiting the development of conspicuous secondary sexual characteristics and, ultimately, enforcing their overall diminutive body size and
-
Is it useful to view the brain as a secondary sexual characteristic?
Ball, Gregory F; Balthazart, Jacques; McCarthy, Margaret M
2014-10-01
Many sex differences in brain and behavior related to reproduction are thought to have evolved based on sexual selection involving direct competition for mates during male-male competition and female choice. Therefore, certain aspects of brain circuitry can be viewed as secondary sexual characteristics. The study of proximate causes reveals that sex differences in the brain of mammals and birds reflect organizational and activational effects of sex steroids as articulated by Young and collaborators. However, sex differences in brain and behavior have been identified in the cognitive domain with no obvious link to reproduction. Recent views of sexual selection advocate for a broader view of how intra-sexual selection might occur including such examples as competition within female populations for resources that facilitate access to mates rather than mating competition per se. Sex differences can also come about for other reasons than sexual selection and recent work on neuroendocrine mechanisms has identified a plethora of ways that the brain can develop in a sex specific manner. Identifying the brain as sexually selected requires careful hypothesis testing so that one can link a sex-biased aspect of a neural trait to a behavior that provides an advantage in a competitive mating situation. Copyright © 2014 Elsevier Ltd. All rights reserved.
-
Sun, Zhi-Hui; Zhou, Li; Li, Zhi; Liu, Xiao-Chun; Li, Shui-Sheng; Wang, Yang; Gui, Jian-Fang
2017-06-01
Dead end (dnd), vertebrate-specific germ cell marker, had been demonstrated to be essential for primordial germ cell (PGC) migration and survival, and the link between PGC number and sex change had been revealed in some teleost species, but little is known about dnd in hermaphroditic vertebrates. In the present study, a protogynous hermaphroditic orange-spotted grouper (Epinephelus coioides) dnd homologue (Ecdnd) was identified and characterized. Quantitative real-time PCR and in situ hybridization analysis revealed a dynamic and sexually dimorphic expression pattern in PGCs and germ cells of gonads. During sex changing, the Ecdnd transcript sharply increased in early transitional gonad, reached the highest level at late transitional gonad stage, and decreased after testis maturation. Visualization of zebrafish PGCs by injecting with RFP-Ecdnd-3'UTR RNA and GFP-zfnanos3-3'UTR RNA confirmed importance of Ecdnd 3'UTR for the PGC distribution. In addition, knockdown of EcDnd by using antisense morpholinos (MO) caused the ablation of PGCs in orange-spotted grouper. Therefore, the current data indicate that Ecdnd is essential for PGCs survival and may serve as a useful germ cell marker during gametogenesis in hermaphroditic grouper. Copyright © 2017 Elsevier Inc. All rights reserved.
-
Olver, Mark E; Mundt, James C; Thornton, David; Beggs Christofferson, Sarah M; Kingston, Drew A; Sowden, Justina N; Nicholaichuk, Terry P; Gordon, Audrey; Wong, Stephen C P
2018-04-30
The present study sought to develop updated risk categories and recidivism estimates for the Violence Risk Scale-Sexual Offense version (VRS-SO; Wong, Olver, Nicholaichuk, & Gordon, 2003-2017), a sexual offender risk assessment and treatment planning tool. The overarching purpose was to increase the clarity and accuracy of communicating risk assessment information that includes a systematic incorporation of new information (i.e., change) to modify risk estimates. Four treated samples of sexual offenders with VRS-SO pretreatment, posttreatment, and Static-99R ratings were combined with a minimum follow-up period of 10-years postrelease (N = 913). Logistic regression was used to model 5- and 10-year sexual and violent (including sexual) recidivism estimates across 6 different regression models employing specific risk and change score information from the VRS-SO and/or Static-99R. A rationale is presented for clinical applications of select models and the necessity of controlling for baseline risk when utilizing change information across repeated assessments. Information concerning relative risk (percentiles) and absolute risk (recidivism estimates) is integrated with common risk assessment language guidelines to generate new risk categories for the VRS-SO. Guidelines for model selection and forensic clinical application of the risk estimates are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
-
Effectiveness of the Sexual Attitude Restructuring Curriculum amongst Taiwanese Graduate Students
Lin, Yi-Li; Lin, Yen-Chin
2018-01-01
This article discusses the effectiveness of the Sexual Attitude Restructuring (SAR) curriculum in developing positive sexual attitudes amongst Taiwanese graduate students in human sexuality. Through purposive sampling, 32 graduate students in human sexuality were selected to participate in the study. Before and after providing participants with a…
-
The psychosexual profile of sexual assistants: an internet-based explorative study.
Directory of Open Access Journals (Sweden)
Erika Limoncin
Full Text Available Sexual assistance may have some aspects that resemble prostitution and others that might lead one to think of sexual assistants as similar to a group of subjects whose sexual object is disability (devotees. In this study, we investigate whether a rigorous selection and training process on the part of specialised organisations may reduce the risk of training subjects with an atypical sexual interest and behaviours resembling prostitution.The study population consisted of 152 subjects defining themselves as sexual assistants. Subjects were initially contacted on websites specifically dedicated to sexual assistants and prostitutes. One hundred and twenty subjects were selected, by propensity score analysis, and studied by means of a modified version of a semi-structured questionnaire previously developed to investigate a population of subjects attracted by disability.The study group was composed of 80 trained and 40 untrained sexual assistants, with mean ages of 41.5 (SD +/-12.58 and 44.5 (SD +/-11.62, respectively. A significant number of untrained subjects affirmed that their motivation in carrying out sexual assistance was of a remunerative nature, while this number was lower among the trained assistants (p = 0.001. Nearly all untrained subjects claimed to do one or more of the following activities during sexual assistance: sexual intercourse, oral sex, and masturbation. Among the trained subjects, however, only 47.5% claimed to do one or more of these activities, which means that there is a significant gap between trained and untrained assistants (p<0.0001. The existence of an atypical sexual interest was more evident between untrained rather than between trained subjects (p<0.0001.Sexual assistance represents a way through which people affected by disabilities may attain the right to explore their sexuality in a safe setting. This can be guaranteed only if sexual assistants are trained and carefully selected by specialised organisations.
-
Directory of Open Access Journals (Sweden)
Shcherbakov Victor P
2010-03-01
Full Text Available Abstract Consistent holistic view of sexual species as the highest form of biological existence is presented. The Weismann's idea that sex and recombination provide the variation for the natural selection to act upon is dominated in most discussions of the biological meaning of the sexual reproduction. Here, the idea is substantiated that the main advantage of sex is the opposite: the ability to counteract not only extinction but further evolution as well. Living systems live long owing to their ability to reproduce themselves with a high fidelity. Simple organisms (like bacteria reach the continued existence due to the high fidelity of individual genome replication. In organisms with a large genome and complex development, the achievable fidelity of DNA replication is not enough for the precise reproduction of the genome. Such species must be capable of surviving and must remain unchanged in spite of the continuous changes of their genes. This problem has no solution in the frame of asexual ("homeogenomic" lineages. They would rapidly degrade and become extinct or blurred out in the course of the reckless evolution. The core outcome of the transition to sexual reproduction was the creation of multiorganismic entity - biological species. Individual organisms forfeited their ability to reproduce autonomously. It implies that individual organisms forfeited their ability to substantive evolution. They evolve as a part of the biological species. In case of obligatory sexuality, there is no such a thing as synchronic multi-level selection. Natural selection cannot select anything that is not a unit of reproduction. Hierarchy in biology implies the functional predestination of the parts for the sake of the whole. A crucial feature of the sexual reproduction is the formation of genomes of individual organisms by random picking them over from the continuously shuffled gene pool instead of the direct replication of the ancestor's genome. A clear anti
-
Li, Chunyan; Cheng, Zixi; Wu, Taiwen; Liang, Xiao; Gaoshan, Junjian; Li, Lihe; Hong, Ping; Tang, Kun
2017-08-25
A growing prevalence of unexpected pregnancies and younger age of sexual debut is observed among Chinese young people, while they lack formal sexuality education from schools and parents. It is necessary to measure their knowledge level of sexual and reproductive health, and how such knowledge associates with their sexual behaviors and reproductive health outcomes, which would shed light on the effectiveness of sexuality education in China. An Internet-based questionnaire survey was conducted from January to August, 2015. 130 colleges were selected from eastern, central, and western parts China with a good balance of geographic distributions. The survey link was subsequently delivered to the focal points in each college for voluntary participation, targeting on undergraduates aged 18 ~ 25. Information on demographics, experience of school-based sexuality education (defined as any course introducing information on sexual and reproductive health) and SRH knowledge quiz was collected. Multivariate linear regression and logistic regression were applied to explore the relationship between students' SRH knowledge, sexual behaviors and reproductive health outcomes, such as sexual intercourse (penetrative sex by vaginal or anal), unprotected sex, pregnancy and abortion, etc. A total sample of 17,966 Chinese college students (mean age = 20.2, 60.4% female) eventually entered the analysis. Only 55.6% of the respondents self-reported having received sexuality education before, and they scored significantly higher (2.33/4.00) in the SRH knowledge quiz than those who had not (1.75/4.00). Among the sexually experienced students (n = 3639, 20.2%), both males and females with higher SRH knowledge were less likely to report having experience of (partner's) pregnancy or abortion (OR sexually experienced males, those with higher SRH knowledge had a slightly later age of sexual debut (coefficient = 0.28, p sexual intercourses (OR = 0.82, 95%C.I.: 0.69 ~ 0.96). Students
-
Correlated evolution of migration and sexual dichromatism in the New World orioles (icterus).
Friedman, Nicholas R; Hofmann, Christopher M; Kondo, Beatrice; Omland, Kevin E
2009-12-01
The evolution of sexual dimorphism has long been attributed to sexual selection, specifically as it would drive repeated gains of elaborate male traits. In contrast to this pattern, New World oriole species all exhibit elaborate male plumage, and the repeated gains of sexual dichromatism observed in the genus are due to losses of female elaboration. Interestingly, most sexually dichromatic orioles belong to migratory or temperate-breeding clades. Using character scoring and ancestral state reconstructions from two recent studies in Icterus, we tested a hypothesis of correlated evolution between migration and sexual dichromatism. We employed two discrete phylogenetic comparative approaches: the concentrated changes test and Pagel's discrete likelihood test. Our results show that the evolution of these traits is significantly correlated (CCT: uncorrected P model of character evolution suggests that gains of sexual dichromatism are 23 times more likely to occur in migratory taxa. This study demonstrates that a life-history trait with no direct relationship with sexual selection has a strong influence on the evolution of sexual dichromatism. We recommend that researchers further investigate the role of selection on elaborate female traits in the evolution of sexual dimorphism.
-
"She Got Spoilt": Perceptions of Victims of Child Sexual Abuse in Ghana.
Böhm, Bettina
2017-10-01
International research has commented on social stigma as a key reason for nondisclosure of child sexual abuse. However, the actual components of this social stigma frequently remain unexplored. The present study deals with perceptions of consequences of child sexual abuse among professionals and laypeople in Ghana (N = 44), employing a bystander perspective. As a qualitative study using a grounded theory framework, it considers these consequences in light of their underlying beliefs about child and adolescent development, particularly in relation to gender-based expectations placed on girls and boys. Consequences of child sexual abuse could be divided into sexual health consequences, beliefs about "destroyed innocence" and beliefs about a "destroyed future," which were strongly related to the sexual nature of the violence perpetrated. These perceived consequences of child sexual abuse hold implications for what surviving child sexual abuse means on a social level. Implications for practice are discussed on the basis of the data analysis.
-
DEFF Research Database (Denmark)
Froeding, LP; Ottesen, C; Rung-Hansen, H
2014-01-01
Radical vaginal trachelectomy (RVT) offers low complication rate, good survival, and possibility for future childbearing for young women with early stage cervical cancer. However, the literature on quality of life (QOL) and sexual functioning in patients undergoing RVT is scarce.......Radical vaginal trachelectomy (RVT) offers low complication rate, good survival, and possibility for future childbearing for young women with early stage cervical cancer. However, the literature on quality of life (QOL) and sexual functioning in patients undergoing RVT is scarce....
-
Diet selection and seasonal dietary switch of a large sexually dimorphic herbivore
Shannon, Graeme; Mackey, Robin L.; Slotow, Rob
2013-01-01
Although diet selection and the physiological adaptations of grazers and browsers have been widely studied, much less is known about mixed-feeders that target both grass and woody species. The ability to switch diet allows the individual to respond to spatial and temporal changes in forage abundance and quality, providing a key mechanism for large herbivores to exploit heterogeneous environments. We compare diet selection and timing of the seasonal dietary switch for a large-bodied, sexually dimorphic mixed-feeder, the African elephant. The study was carried out on a small population of elephants (n = 48) in the Pongola Game Reserve (PGR), South Africa. Sex-specific dietary composition evaluated from feeding behaviour correlated with composition in dung samples from individuals of known sex. Grass was strongly preferred during the wet season and browse in the winter dry season. However, adult male elephants switched from browse to grass earlier, and consumed a greater overall proportion of grass in their diet, compared with adult females and their associated family groups. Male elephants also spent more time in grassland habitats, and expanded their ranges to a greater extent than females following the end of the dry season. Our results suggest that smaller adult body size, high nutritional demands of offspring, and the constraints of sociality have contributed to female elephants in PGR resolving their diet selection strategies to target higher quality foraging opportunities, whilst males appear to be adopting a rate maximizing approach. The behavioural differences between the sexes are pronounced, which has implications for elephant management approaches that are typically focussed at the population level.
-
Gershman, Susan N.; Mitchell, Christopher; Sakaluk, Scott K.; Hunt, John
2012-01-01
Nuptial food gifts function to enhance male fertilization success, but their consumption is not always beneficial to females. In decorated crickets, the spermatophore transferred at mating includes a gelatinous mass, the spermatophylax, which is consumed by females after mating. However, females often discard spermatophylaxes shortly after mating, whereupon they terminate sperm transfer. We hypothesized that females discard gifts based on their assessment of the gift itself, and specifically the composition of free amino acids. We tested this hypothesis by comparing spermatophylaxes discarded by females after mating with those that were destined to be fully consumed, and employed multivariate selection analysis to quantify the strength and form of multivariate sexual selection operating on the free amino acid composition of gifts. The analysis yielded a saddle-shaped fitness surface with two local peaks. Different amino acid profiles appear to elicit continued feeding on the spermatophylax either because they offer the same level of gustatory appeal, or because they differentially affect both the gustatory appeal and texture of the spermatophylax. We conclude that the gustatory response of females to males' nuptial food gifts represents an important avenue of post-copulatory mate choice, imposing significant sexual selection on the free amino acid composition of the spermatophylax. PMID:22357263
-
Sexual harassment against nurses in Turkey.
Celik, Yusuf; Celik, Sevilay Senol
2007-01-01
To identify the prevalence and sources of sexual harassment against nurses in Turkey, its consequences, and factors affecting harassment experiences. Descriptive survey. Participants (N=622) were selected from nurses working in eight Ministry of Health hospitals in Turkey. Participants were surveyed with a Sexual Harassment Questionnaire, consisting of the sociodemographic characteristics of participants, types of sexual harassment, sources, feelings, ramifications, and ways to cope with sexual harassment behaviors. Frequency and percentage distributions, chi-square, and logistic regression were used for data analysis. The results showed 37.1% of participants had been harassed sexually. Physicians were identified as the primary instigators of sexual harassment. The most common reactions against harassers were anger and fear; frequently reported negative effects of sexual harassment were disturbed mental health function, decline in job performance, and headache. "Did nothing" was the coping method used most commonly by the nurses. About 80% of sexually harassed nurses did not report the incident of sexual harassment to hospital administration. The lower working status and power of nurses in the workplace, poor working conditions in healthcare settings, and insufficient administrative mechanisms, including the present law and regulations against sexual harassers, were identified as important factors in the work environment in Turkey.
-
Sexual exploitation and labor during adolescence: A case study
Directory of Open Access Journals (Sweden)
Luciana Dutra-Thomé
2011-09-01
Full Text Available The present article focused on the perception of sexual exploitation as a job, using a single case study design. The aim of the study was to investigate the case of a 14 year-old girl, involved in commercial sexual exploitation, who considered this situation as her labor activity. A content analysis showed protective and risk factors as categories, especially related to her labor activities. The girl perceived the sexual exploitation activity as a job that provided autonomy, subsistence, and survival. The study revealed that the negative effects of working during adolescence may bring consequences to health and development. Youth work may be defined as a risk factor, especially when the labour conditions are not adequate and protected.
-
Ro, Annie; Ayala, George; Paul, Jay; Choi, Kyung-Hee
2013-01-01
While many studies have established the relationship between experiences of racism and sexual risk among men of colour who have sex with men, the pathways by which this occurs are underdeveloped. To address this gap, we must better investigate the lived realities of racism in the gay community. In this study, we had the unique opportunity to examine experiences of racism among African American, Asian/Pacific Islander and Latino men who have sex with men living in Los Angeles through focus groups and individual in-depth interviews. We found three themes of racism: exclusion from West Hollywood and the mainstream gay community, sexual rejection based on race/ethnicity and sexual stereotypes. There were differences across the three racial groups in the experiences of each theme, however. We then considered how racism impacted partner selection and found that race played a salient role in determining power differentials within mixed-race partnerships. Finally, we discussed several future areas for research that can better establish pathways between racism and sexual risk.
-
Ayala, George; Paul, Jay; Choi, Kyung-Hee
2013-01-01
While many studies have established the relationship between experiences of racism and sexual risk among men who have sex with men of colour, the pathways by which this occurs are underdeveloped. To address this gap, we must better investigate the lived realities of racism in the gay community. In this study, we had the unique opportunity to examine experiences of racism among African American, Latino and Asian/Pacific Islander men who have sex with men living in Los Angeles through focus groups and individual in-depth interviews. We found three themes of racism: exclusion from West Hollywood and the mainstream gay community, sexual rejection based on race/ethnicity, and sexual stereotypes. There were differences across the three racial groups in the experiences of each theme, however. We then considered how racism impacted partner selection and found that race played a salient role in determining power differentials within mixed-race partnerships. Finally, we discussed several future areas for research that can better establish pathways between racism and sexual risk. PMID:23659363
-
Sexual Dimorphism in Bite Performance Drives Morphological Variation in Chameleons
da Silva, Jessica M.; Herrel, Anthony; Measey, G. John; Tolley, Krystal A.
2014-01-01
Phenotypic performance in different environments is central to understanding the evolutionary and ecological processes that drive adaptive divergence and, ultimately, speciation. Because habitat structure can affect an animal’s foraging behaviour, anti-predator defences, and communication behaviour, it can influence both natural and sexual selection pressures. These selective pressures, in turn, act upon morphological traits to maximize an animal’s performance. For performance traits involved in both social and ecological activities, such as bite force, natural and sexual selection often interact in complex ways, providing an opportunity to understand the adaptive significance of morphological variation with respect to habitat. Dwarf chameleons within the Bradypodion melanocephalum-Bradypodion thamnobates species complex have multiple phenotypic forms, each with a specific head morphology that could reflect its use of either open- or closed-canopy habitats. To determine whether these morphological differences represent adaptations to their habitats, we tested for differences in both absolute and relative bite performance. Only absolute differences were found between forms, with the closed-canopy forms biting harder than their open-canopy counterparts. In contrast, sexual dimorphism was found for both absolute and relative bite force, but the relative differences were limited to the closed-canopy forms. These results indicate that both natural and sexual selection are acting within both habitat types, but to varying degrees. Sexual selection seems to be the predominant force within the closed-canopy habitats, which are more protected from aerial predators, enabling chameleons to invest more in ornamentation for communication. In contrast, natural selection is likely to be the predominant force in the open-canopy habitats, inhibiting the development of conspicuous secondary sexual characteristics and, ultimately, enforcing their overall diminutive body size and
-
Sexual dimorphism in bite performance drives morphological variation in chameleons.
Directory of Open Access Journals (Sweden)
Jessica M da Silva
Full Text Available Phenotypic performance in different environments is central to understanding the evolutionary and ecological processes that drive adaptive divergence and, ultimately, speciation. Because habitat structure can affect an animal's foraging behaviour, anti-predator defences, and communication behaviour, it can influence both natural and sexual selection pressures. These selective pressures, in turn, act upon morphological traits to maximize an animal's performance. For performance traits involved in both social and ecological activities, such as bite force, natural and sexual selection often interact in complex ways, providing an opportunity to understand the adaptive significance of morphological variation with respect to habitat. Dwarf chameleons within the Bradypodion melanocephalum-Bradypodion thamnobates species complex have multiple phenotypic forms, each with a specific head morphology that could reflect its use of either open- or closed-canopy habitats. To determine whether these morphological differences represent adaptations to their habitats, we tested for differences in both absolute and relative bite performance. Only absolute differences were found between forms, with the closed-canopy forms biting harder than their open-canopy counterparts. In contrast, sexual dimorphism was found for both absolute and relative bite force, but the relative differences were limited to the closed-canopy forms. These results indicate that both natural and sexual selection are acting within both habitat types, but to varying degrees. Sexual selection seems to be the predominant force within the closed-canopy habitats, which are more protected from aerial predators, enabling chameleons to invest more in ornamentation for communication. In contrast, natural selection is likely to be the predominant force in the open-canopy habitats, inhibiting the development of conspicuous secondary sexual characteristics and, ultimately, enforcing their overall diminutive
-
Rationally Irrational: The Case of Sexual Burglary.
Pedneault, Amelie; Beauregard, Eric; Harris, Danielle A; Knight, Raymond A
2015-08-01
The present study investigated rationality in sexually motivated burglaries. Specifically, we analyzed the situational cues identified by sexual burglars in their target selection. The research project investigated 224 individual incidents of residential burglary with apparent sexual motivations. Situational characteristics of the incidents were recorded and analyzed using forward sequential regressions. Results indicated that most sexually motivated burglaries occurred in occupied residences with deficient physical guardianship, when the victim was alone. Violence, theft, penetration, and fetishism were found to be committed in circumstances that increased the benefits and lowered the risks. Results showed that sexual burglary is rational in nature-sexual burglars chose residences that were easy to break into. We found little support for the premise that such opportunities arose while carrying out regular burglaries. Instead, the data indicated that sexual burglars acted opportunistically on situational cues that are markedly dissimilar to those of regular burglars. © The Author(s) 2014.
-
Growth performance and survival of local and white leghorn chicken ...
African Journals Online (AJOL)
This study was conducted to evaluate the comparative growth, sexual maturity, survival, and feed utilization efficiency of local and White Leghorn chicken under intensive management condition. Five groups of each of the two breeds, with 200 baby chicks each, were subjected to appetite feeding with commercial layer\\'s ...
-
Sexual Healthcare for Wounded Warriors with Serious Combat-Related Injuries and Disabilities.
Tepper, Mitchell S
2014-04-01
Short of the rich literature on sexuality in men following spinal cord injury, started largely by physicians and mental health professionals within the United States Department of Veterans Affairs (VA) system following earlier wars, little attention has been paid to the sexual healthcare of wounded warriors with other serious combat-related injuries. The recent wars in Iraq and Afghanistan-Operation Enduring Freedom (OEF), Operation Iraqi Freedom (OIF), and Operation New Dawn (OND)-resulted in physical injuries including traumatic brain injuries (TBIs), amputations, and serious burns. There are wounded warriors who are left blind or deaf, and a significant percent of OEF/OIF/OND warriors acquire other "invisible" injuries. While the signature injury of the war in Iraq is said to be TBI, there are a substantial number of service members surviving with posttraumatic stress disorder (PTSD). Many with serious injury are struggling with co-occurring depression. Furthermore, many of our wounded warriors are surviving with polytrauma (multiple traumatic injuries, i.e., amputation plus burns). One specific constellation of injuries seen too frequently among our service members in Afghanistan is referred to as a Dismounted Complex Blast Injury (DCBI) sometimes resulting in orchiectomy and/or penile injury. As with other blast injuries, burns, shrapnel injuries, vision loss, hearing loss, TBI, and PTSD often accompany DCBIs. All of the above injuries have significant sexual, endocrine, psychological, and relationship issues that need to be addressed. This article presents an overview of the effects of serious, combat-related injuries on sexual health and provides medical and other health professionals a framework within which to address comprehensive sexual healthcare using a medical rehabilitation model. Sexual healthcare for persons with combat-related disabilities presents a complex array of biopsychosocial and relational issues that call for a coordinated
-
"Children are sexually innocent": Iranian parents' understanding of children's sexuality.
Merghati-Khoei, Effat; Abolghasemi, Naria; Smith, Thomas G
2014-04-01
Sexuality education (SE) is hotly contested in the West and there is much abstinence-only education; however, it remains controversial in a variety of contexts, including in Iran. The lack of consensus about children's SE in Muslim societies obliges us to explore different aspects of this topic systematically. The qualitative research presented here was about how Iranian parents perceived children's sexuality. Data from parents of 26 children were collected during four focus group sessions. Informants were selected from Area 5 in West Tehran. This area included 72 primary schools for girls and 82 for boys. The sessions were facilitated by using a semi-structured focus group guide. Content analysis was adopted using combined free and analytical coding to reduce data, to extract meanings, and to categorize domains. One of the three main domains identified, family management of child sexuality, is comprised of the following: (1) understanding of child sexuality, (2) family rules, (3) parent-child interactions, and (4) opposite sex interactions. Parental misinformation, accumulated myths, and ignorance about children's sexual development were evident. Strict family rules and a lack of consistent policy and instruction for SE were also identified. Parents said they were neither well-prepared nor competent to educate their children about sexuality. In fact, a majority of mothers raised "incompetence" as an important determinant in their own parent-child interactions. Societal changes as well as children's socialization patterns have forced parents to accept their children's opposite sex friendships as a reality. Results suggest a community need for developing comprehensive and culturally sensitive SE for schools and parental use.
-
Directory of Open Access Journals (Sweden)
Carlos Cesar de Mello Junior
2011-05-01
Full Text Available The objective of this work was to select surviving breeders of Litopenaeus vannamei from white spot syndrome virus (WSSV outbreak, adapted to local climatic conditions and negatively diagnosed for WSSV and infectious hypodermal and hematopoietic necrosis virus (IHHNV, and to evaluate if this strategy is a viable alternative for production in Santa Catarina, Brazil. A total of 800 males and 800 females were phenotypically selected in a farm pond. Nested-PCR analyses of 487 sexually mature females and 231 sexually mature males showed that 63% of the females and 55% of the males were infected with IHHNV. Animals free of IHHNV were tested for WSSV, and those considered double negative were used for breeding. The post-larvae produced were stocked in nine nursery tanks for analysis. From the 45 samples, with 50 post-larvae each, only two were positive for IHHNV and none for WSSV. Batches of larvae diagnosed free of virus by nested-PCR were sent to six farms. A comparative analysis was carried out in growth ponds, between local post-larvae and post-larvae from Northeast Brazil. Crabs (Chasmagnathus granulata, blue crabs (Callinectes sapidus, and sea hares (Aplysia brasiliana, which are possible vectors of these viruses, were also evaluated. The mean survival was 55% for local post-larvae against 23.4% for post-larvae from the Northeast. Sea hares showed prevalence of 50% and crabs of 67% of WSSV.
-
The Psychosexual Profile of Sexual Assistants: An Internet-Based Explorative Study
Limoncin, Erika; Galli, Debora; Ciocca, Giacomo; Gravina, Giovanni Luca; Carosa, Eleonora; Mollaioli, Daniele; Lenzi, Andrea; Jannini, Emmanuele A.
2014-01-01
Introduction Sexual assistance may have some aspects that resemble prostitution and others that might lead one to think of sexual assistants as similar to a group of subjects whose sexual object is disability (devotees). In this study, we investigate whether a rigorous selection and training process on the part of specialised organisations may reduce the risk of training subjects with an atypical sexual interest and behaviours resembling prostitution. Materials and Methods The study population consisted of 152 subjects defining themselves as sexual assistants. Subjects were initially contacted on websites specifically dedicated to sexual assistants and prostitutes. One hundred and twenty subjects were selected, by propensity score analysis, and studied by means of a modified version of a semi-structured questionnaire previously developed to investigate a population of subjects attracted by disability. Results The study group was composed of 80 trained and 40 untrained sexual assistants, with mean ages of 41.5 (SD +/−12.58) and 44.5 (SD +/−11.62), respectively. A significant number of untrained subjects affirmed that their motivation in carrying out sexual assistance was of a remunerative nature, while this number was lower among the trained assistants (p = 0.001). Nearly all untrained subjects claimed to do one or more of the following activities during sexual assistance: sexual intercourse, oral sex, and masturbation. Among the trained subjects, however, only 47.5% claimed to do one or more of these activities, which means that there is a significant gap between trained and untrained assistants (p<0.0001). The existence of an atypical sexual interest was more evident between untrained rather than between trained subjects (p<0.0001). Conclusions Sexual assistance represents a way through which people affected by disabilities may attain the right to explore their sexuality in a safe setting. This can be guaranteed only if sexual assistants are trained and
-
Sexual Pain Disorders in Spanish Women Drug Users.
Del Río, Francisco Javier; Cabello-Santamaría, Francisco; Cabello-García, Marina A; Aragón-Vela, Jerónimo
2017-01-28
The impact of pain in sexuality, couple relationships and the quality of life is very well known. The relationship between substance abuse and the presence of sexual pain disorder is assessed, together with anxiety and sexual attitudes . Two samples were selected. One sample for women with a history of substance abuse (n = 129), and another one of women nonconsumers (n = 129). The Golombok Rust Inventory of Sexual Satisfaction (GRISS), the Sexual Opinion Survey (SOS) and the State Trait Anxiety Inventory (STAI) questionnaires were used. The results indicate that women consumers obtained a higher mean scores in sexual pain disorder (4.88 > 2.89, that is 65.12%), plus higher mean scores on state anxiety (23.82 > 14.56) and trait anxiety (30.93 > 16.95), and lower average figure in erotophilia (84.93 < 95.81). It was also verified that the period of abstinence does not improve sexual response. Substance consumption affects sexual response in women negatively. Sexual response does not improve with abstinence period.
-
Ybarra, Michele L.; Mitchell, Kimberly J.
2014-01-01
Objective To examine the relation between “sexting,” (sending and sharing sexual photos online via text messaging and in-person) with sexual risk behaviors and psychosocial challenge in adolescence. Methods Data were collected online between 2010 and 2011 with 3,715 randomly selected 13- to 18-year-old youth across the United States. Results Seven percent of youth reported sending or showing someone sexual pictures of themselves, where they were nude or nearly nude, online, via text messaging, or in-person, during the past year. Although females and older youth were more likely to share sexual photos than males and younger youth, the profile of psychosocial challenge and sexual behavior was similar for all youth. After adjusting for demographic characteristics, sharing sexual photos was associated with all types of sexual behaviors assessed (e.g., oral sex, vaginal sex) as well as some of the risky sexual behaviors examined—particularly having concurrent sexual partners and having more past-year sexual partners. Adolescents who shared sexual photos also were more likely to use substances and less likely to have high self-esteem than their demographically similar peers. Conclusions While the media has portrayed “sexting” as a problem caused by new technology, health professionals may be more effective by approaching it as an aspect of adolescent sexual development and exploration and, in some cases, risk-taking and psychosocial challenge. PMID:25266148
-
Ybarra, Michele L; Mitchell, Kimberly J
2014-12-01
To examine the relation between "sexting" (sending and sharing sexual photos online, via text messaging, and in person) with sexual risk behaviors and psychosocial challenge in adolescence. Data were collected online between 2010 and 2011 with 3,715 randomly selected 13- to 18-year-old youth across the United States. Seven percent of youth reported sending or showing someone sexual pictures of themselves, in which they were nude or nearly nude, online, via text messaging, or in person, during the past year. Although females and older youth were more likely to share sexual photos than males and younger youth, the profile of psychosocial challenge and sexual behavior was similar for all youth. After adjusting for demographic characteristics, sharing sexual photos was associated with all types of sexual behaviors assessed (e.g., oral sex, vaginal sex) as well as some of the risky sexual behaviors examined-particularly having concurrent sexual partners and having more past-year sexual partners. Adolescents who shared sexual photos also were more likely to use substances and less likely to have high self-esteem than their demographically similar peers. Although the media has portrayed sexting as a problem caused by new technology, health professionals may be more effective by approaching it as an aspect of adolescent sexual development and exploration and, in some cases, risk-taking and psychosocial challenge. Copyright © 2014 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.
-
[Influence of cumulated sexual trauma on sexual life and relationship of a patient].
Sobański, Jerzy A; Klasa, Katarzyna; Cyranka, Katarzyna; Müldner-Nieckowski, Lukasz; Dembińska, Edyta; Rutkowski, Krzysztof; Smiatek-Mazgaj, Bogna; Mielimaka, Michal
2014-01-01
The assessment of links of accumulated traumatic events of a sexual nature, recollected from the past, with the current functioning of the patients in the area of sexual life and relationship. Comorbidity of memories of traumatic sexual events from childhood and puberty in patients with the features of their current partner relationships and sexual life were analyzed on the basis of Live Inventory completed by 2,582 women and 1,347 men, before treatment in day hospital (years 1980-2002). The accumulation was evaluated for a combination of two or three selected events. The presence of relatively numerous traumatic events in the field of sexuality early initiation or enforced initiation, incest or its attempt, sub-optimal sexual education and punishment for masturbation was indicated. In some patients, these events occurred simultaneously. Especially in women, the presence in the same person of two or three aggravating circumstances of life was associated with a higher risk of among others fleeting, casual sexual contacts, marriage under the influence of environment pressures, reluctance to partner. Increased accumulation - the presence in the same patient of more than one adverse circumstances associated with sexual development - leads to a higher incidence of interference in relationship with a partner including the elements of sexual dysfunction. The obtained results are generally consistent with clinical observations and literature despite different, simplified methodology of the study based on the analysis of single variables from questionnaire interviews. Finding fewer links in the group of men can be explained by their much lower number in the study group and less frequent burdening with certain traumatic events or different experiencing.
-
Selection based on the size of the black tie of the great tit may be reversed in urban habitats.
Senar, Juan Carlos; Conroy, Michael J; Quesada, Javier; Mateos-Gonzalez, Fernando
2014-07-01
A standard approach to model how selection shapes phenotypic traits is the analysis of capture-recapture data relating trait variation to survival. Divergent selection, however, has never been analyzed by the capture-recapture approach. Most reported examples of differences between urban and nonurban animals reflect behavioral plasticity rather than divergent selection. The aim of this paper was to use a capture-recapture approach to test the hypothesis that divergent selection can also drive local adaptation in urban habitats. We focused on the size of the black breast stripe (i.e., tie width) of the great tit (Parus major), a sexual ornament used in mate choice. Urban great tits display smaller tie sizes than forest birds. Because tie size is mostly genetically determined, it could potentially respond to selection. We analyzed capture/recapture data of male great tits in Barcelona city (N = 171) and in a nearby (7 km) forest (N = 324) from 1992 to 2008 using MARK. When modelling recapture rate, we found it to be strongly influenced by tie width, so that both for urban and forest habitats, birds with smaller ties were more trap-shy and more cautious than their larger tied counterparts. When modelling survival, we found that survival prospects in forest great tits increased the larger their tie width (i.e., directional positive selection), but the reverse was found for urban birds, with individuals displaying smaller ties showing higher survival (i.e., directional negative selection). As melanin-based tie size seems to be related to personality, and both are heritable, results may be explained by cautious personalities being favored in urban environments. More importantly, our results show that divergent selection can be an important mechanism in local adaptation to urban habitats and that capture-recapture is a powerful tool to test it.
-
Frentiu, Francesca D; Adamski, Marcin; McGraw, Elizabeth A; Blows, Mark W; Chenoweth, Stephen F
2009-01-01
Abstract Background The native Australian fly Drosophila serrata belongs to the highly speciose montium subgroup of the melanogaster species group. It has recently emerged as an excellent model system with which to address a number of important questions, including the evolution of traits under sexual selection and traits involved in climatic adaptation along latitudinal gradients. Understanding the molecular genetic basis of such traits has been limited by a lack of genomic resources for thi...
-
Juma, Milka; Alaii, Jane; Bartholomew, L Kay; Askew, Ian; Van den Born, Bart
2013-07-25
Some studies show orphanhood to be associated with increased sexual risk-taking while others have not established this relationship, but have found factors other than orphanhood as predictors of sexual risk behaviours and outcomes among adolescents. This study examines community members' perceptions of how poverty influences adolescent sexual behaviour and outcomes in four districts of Nyanza Province, Kenya. Eight study sites within the four districts were randomly selected. Focus group discussions were conducted with a purposive sample of adolescents, parents and caregivers. Key informant interviews were undertaken with a purposive sample of community leaders, child welfare and healthcare workers, and adolescents. The two methods elicited information on factors perceived to predispose adolescent orphans and non-orphans to sexual risks. Data were analysed through line-by-line coding, grouped into families and retrieved as themes and sub-themes. Participants included 147 adolescents and parents/caregivers in 14 focus groups and 13 key informants. Poverty emerged as a key predisposing factor to sexual risk behaviour among orphans and non-orphans. Poverty was associated with lack of food, poor housing, school dropout, and engaging in income generating activities, all of which increase their vulnerability to transactional sex, early marriage, sexual experimentation, and the eventual consequences of increased risk of unintended pregnancies and STI/HIV. Poverty was perceived to contribute to increasing sexual risks among orphan and non-orphan adolescents through survival strategies adopted to be able to meet their basic needs. Policies for prevention and intervention that target adolescents in a generalized poverty and HIV epidemic should integrate economic empowerment for caregivers and life skills for adolescents to reduce vulnerabilities of orphan and non-orphan adolescents to sexual risk behaviour.
-
From Evolutionary Allometry to Sexual Display: (A Reply to Holman and Bro-Jørgensen).
Raia, Pasquale; Passaro, Federico; Carotenuto, Francesco; Meiri, Shai; Piras, Paolo
2016-08-01
Conventional wisdom holds that the complex shapes of deer antlers are produced under the sole influence of sexual selection. We questioned this view by demonstrating that trends for increased body size evolution passively yield more-complex ornaments, even in organisms where no effect of sexual selection is possible, with similar allometric slopes. Recent investigations suggest that sexual selection on antlers of larger deer species is stronger than that in smaller species; hence, the use of conspicuous antlers for display in large male deer is a secondary function driven by especially intense sexual selection on these large-bodied species. Since ancestral deer were small and had very simple antlers, such an intense selection on antlers shape was probably absent in early deer. Therefore, the evolution of complex ornaments is coupled with body size evolution, even in deer.
-
Sexual orientation in males and the evolution of anisogamy.
Reed, Lawrence Ian
2010-02-01
How might homosexual orientation have evolved and been maintained? Several adaptationist explanations have been examined in attempt to reconcile the presence of same-sex sexual behaviors with traditional selection-based theory, showing little empirical support. The current paper presents a novel adaptationist explanation for the evolution and maintenance of same-sex sexual behaviors in males, both between- and within-species, related to the evolution of anisogamy. Under conditions of isogamy, sexual reproduction occurs between individuals with gametes of similar morphology. With the evolution of anisogamy came greater specificity on the types of individuals that would produce offspring when mated with (i.e. those with opposing gamete sizes). It is suggested that with this evolutionary change, a specified psychological adaptation orienting individuals primarily towards mating partners with newly opposing gamete sizes was then selected for. It is thus hypothesized that sexual orientation will vary along the anisogamy-isogamy continuum, with homosexual orientation being associated with closer approximations towards isogamy. This hypothesis leads to two specific predictions. First, in comparisons between species, the presence of same-sex sexual behaviors will be more likely to occur as sperm to egg ratios approach 1:1. Second, in comparisons within species, those individuals with greater sperm lengths will be more likely to exhibit same-sex sexual behaviors than those with lesser sperm lengths. Examination of the present hypothesis stands to greatly increase our knowledge of the selective forces shaping both biological and psychological evolution.
-
Sexual Violence Infrastructures (SVIs): Hotels and Cyberspace as ...
African Journals Online (AJOL)
The study draws from a prominent criminology theory – routine activities theory to analyse the necessary conditions under which sexual predators select potential targets or victims. These conditions include the availability of three essential factors: existence of a motivated offender (sexual predator), an attractive target, and ...
-
Sexual Assault against Female Nigerian Students | Kullima | African ...
African Journals Online (AJOL)
Sexual assault is a common social disorder among students in our tertiary institutions. This study ascertains the extent and effect of sexual assault among Nigerian students. Two hundred and Sixty Eight structured questionnaires were distributed to randomly selected students in 4 tertiary institutions, information on socio ...
-
Satisfação sexual na demência Sexual satisfaction in dementia
Directory of Open Access Journals (Sweden)
Marcela Moreira Lima Nogueira
2013-01-01
Full Text Available CONTEXTO: A demência pode resultar em comprometimento da intimidade e sexualidade de casais idosos. OBJETIVOS: Avaliar alterações na atividade sexual, bem como os fatores de satisfação e/ou insatisfação sexual de casais nos quais um dos parceiros possua demência. MÉTODO: Busca nas bases de dados ISI, PubMed/Medline e SciELO de artigos sobre sexualidade na demência, entre janeiro de 1990 e março de 2012, utilizando as palavras-chave: "demência", "satisfação sexual", "intimidade" e "sexualidade". RESULTADOS: Foram encontrados 12 artigos. A sobrecarga de cuidados e a alteração de papéis na relação conjugal foram consideradas as principais causas para o declínio da atividade sexual. A disfunção erétil em pacientes e cônjuges, a capacidade decisória para o consentimento da relação sexual por parte do paciente demenciado e os problemas referentes à idade e à saúde (física e emocional do cônjuge e/ou paciente foram os fatores associados à insatisfação sexual. CONCLUSÃO: A intimidade e a atividade sexual dos casais em que um dos parceiros é portador de demência são influenciadas negativamente pela relação de cuidados decorrente da doença e pela sobrecarga dos cônjuges. Por outro lado, a atividade sexual pode ser positivamente substituída por demonstrações de carinho e empatia entre os cônjuges.BACKGROUND: Dementia may result on impairment in intimacy and sexuality of elderly couples. OBJECTIVES: Evaluate changes in sexual activity, as well as the factors which cause sexual satisfaction and/or dissatisfaction in couples in which one of the partners has dementia. METHOD: A search at ISI, PubMed/Medline and SciELO was made for articles about sexuality in dementia, from January 1990 to March 2012, using the keywords: "dementia", "sexual satisfaction", "intimacy" and "sexuality". RESULTS: Twelve articles were selected. The burden of care and the change of roles in couples' relationship were the main reasons for
-
Sexuality in older adults: Clinical and psychosocial dilemmas
Isha Dhingra; Avinash De Sousa; Sushma Sonavane
2016-01-01
The present review aims to throw some light on the various aspects of sexuality in older adults and the challenges faced by medical professionals working in this area. Keyword searches using the terms "sexuality," "sexual dysfunction," "geriatric," "old age," and others in combination were carried out on PubMed, Google Scholar, and the Cochrane Database of Systematic Reviews. Relevant clinical trials, case studies, and review papers were selected. This was further supplemented with the clinic...
-
Primate brain architecture and selection in relation to sex.
Lindenfors, Patrik; Nunn, Charles L; Barton, Robert A
2007-05-10
Social and competitive demands often differ between the sexes in mammals. These differing demands should be expected to produce variation in the relative sizes of various brain structures. Sexual selection on males can be predicted to influence brain components handling sensory-motor skills that are important for physical competition or neural pathways involving aggression. Conversely, because female fitness is more closely linked to ecological factors and social interactions that enable better acquisition of resources, social selection on females should select for brain components important for navigating social networks. Sexual and social selection acting on one sex could produce sexual dimorphism in brain structures, which would result in larger species averages for those same brain structures. Alternatively, sex-specific selection pressures could produce correlated effects in the other sex, resulting in larger brain structures for both males and females of a species. Data are presently unavailable for the sex-specific sizes of brain structures for anthropoid primates, but under either scenario, the effects of sexual and social selection should leave a detectable signal in average sizes of brain structures for different species. The degree of male intra-sexual selection was positively correlated with several structures involved in autonomic functions and sensory-motor skills, and in pathways relating to aggression and aggression control. The degree of male intra-sexual selection was not correlated with relative neocortex size, which instead was significantly positively correlated with female social group size, but negatively correlated with male group size. Sexual selection on males and social selection on females have exerted different effects on primate brain architecture. Species with a higher degree of male intra-sexual selection carry a neural signature of an evolutionary history centered on physical conflicts, but no traces of increased demands on
-
Primate brain architecture and selection in relation to sex
Directory of Open Access Journals (Sweden)
Nunn Charles L
2007-05-01
Full Text Available Abstract Background Social and competitive demands often differ between the sexes in mammals. These differing demands should be expected to produce variation in the relative sizes of various brain structures. Sexual selection on males can be predicted to influence brain components handling sensory-motor skills that are important for physical competition or neural pathways involving aggression. Conversely, because female fitness is more closely linked to ecological factors and social interactions that enable better acquisition of resources, social selection on females should select for brain components important for navigating social networks. Sexual and social selection acting on one sex could produce sexual dimorphism in brain structures, which would result in larger species averages for those same brain structures. Alternatively, sex-specific selection pressures could produce correlated effects in the other sex, resulting in larger brain structures for both males and females of a species. Data are presently unavailable for the sex-specific sizes of brain structures for anthropoid primates, but under either scenario, the effects of sexual and social selection should leave a detectable signal in average sizes of brain structures for different species. Results The degree of male intra-sexual selection was positively correlated with several structures involved in autonomic functions and sensory-motor skills, and in pathways relating to aggression and aggression control. The degree of male intra-sexual selection was not correlated with relative neocortex size, which instead was significantly positively correlated with female social group size, but negatively correlated with male group size. Conclusion Sexual selection on males and social selection on females have exerted different effects on primate brain architecture. Species with a higher degree of male intra-sexual selection carry a neural signature of an evolutionary history centered on
-
Garcia, Justin R; MacKillop, James; Aller, Edward L; Merriwether, Ann M; Wilson, David Sloan; Lum, J Koji
2010-11-30
Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection), little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR) polymorphism in exon III of the human dopamine D4 receptor gene (DRD4) has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity. We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+) report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a "one-night stand") and report a more than 50% increase in instances of sexual infidelity. DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism.
-
Associations between Dopamine D4 Receptor Gene Variation with Both Infidelity and Sexual Promiscuity
Garcia, Justin R.; MacKillop, James; Aller, Edward L.; Merriwether, Ann M.; Wilson, David Sloan; Lum, J. Koji
2010-01-01
Background Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection), little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR) polymorphism in exon III of the human dopamine D4 receptor gene (DRD4) has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity. Methodology/Principal Findings We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+) report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a “one-night stand”) and report a more than 50% increase in instances of sexual infidelity. Conclusions/Significance DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism. PMID:21152404
-
Directory of Open Access Journals (Sweden)
Justin R Garcia
2010-11-01
Full Text Available Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection, little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR polymorphism in exon III of the human dopamine D4 receptor gene (DRD4 has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity.We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+ report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a "one-night stand" and report a more than 50% increase in instances of sexual infidelity.DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism.
-
Qualitative evaluation of selected social factors that impact sexual ...
African Journals Online (AJOL)
Objectives: This study was designed to explore the sexual behaviour of students in a metropolitan Durban University of Technology in KwaZulu-Natal to understand the social factors underlying their risk of HIV infection. Methods: This is a qualitative study that used cluster sampling where the population was stratified by ...
-
Sexual dysfunction and cardiovascular diseases: a systematic review of prevalence
Directory of Open Access Journals (Sweden)
Elisabete Rodrigues Nascimento
2013-11-01
Full Text Available The aim of this study was to conduct a systematic review of the literature regarding the prevalence of sexual dysfunction in patients with cardiovascular diseases. An article search of the ISI Web of Science and PubMed databases using the search terms "sexual dysfunction”, “cardiovascular diseases”, “coronary artery disease", “myocardial infarct" and “prevalence” was performed. In total, 893 references were found. Non-English-language and repeated references were excluded. After an abstract analysis, 91 references were included for full-text reading, and 24 articles that evaluated sexual function using validated instruments were selected for this review. This research was conducted in October 2012, and no time restrictions were placed on any of the database searches. Reviews and theoretical articles were excluded; only clinical trials and epidemiological studies were selected for this review. The studies were mostly cross-sectional, observational and case-control in nature; other studies used prospective cohort or randomized clinical designs. In women, all domains of sexual function (desire, arousal, vaginal lubrication, orgasm, sexual dissatisfaction and pain were affected. The domains prevalent in men included erectile dysfunction and premature ejaculation and orgasm. Sexual dysfunction was related to the severity of cardiovascular disease. When they resumed sexual activity, patients with heart disease reported significant difficulty, including a lack of interest in sex, sexual dissatisfaction and a decrease in the frequency of sexual activity.
-
Evolution and maintenance of sexual size dimorphism: Aligning phylogenetic and experimental evidence
Directory of Open Access Journals (Sweden)
Matjaz eKuntner
2014-06-01
Full Text Available Integrating the insights derived from both phylogenetic and experimental approaches offers a more complete understanding of evolutionary patterns and processes, yet it is rarely a feature of investigations of the evolutionary significance of trait variation. We combine these approaches to reinterpret the patterns and processes in the evolution of female biased sexual size dimorphism in Nephilidae, a spider lineage characterized by the most extreme sexual size dimorphism among terrestrial animals. We use a molecular phylogeny to reconstruct the size evolution for each sex and reveal a case of sexually dimorphic gigantism: both sexes steadily outgrow their ancestral sizes, but the female and male slopes differ, and hence sexual size dimorphism steadily increases. A review of the experimental evidence reveals a predominant net selection for large size in both sexes, consistent with the phylogenetic pattern for females but not for males. Thus, while sexual size dimorphism in spiders most likely originates and is maintained by fecundity selection on females, it is unclear what selection pressures prevent males from becoming as large as females. This integrated approach highlights the dangers of inferring evolutionary significance from experimental studies that isolate the effects of single selection pressures.
-
Vannier, Sarah A; Rosen, Natalie O
2017-03-01
Sexual problems are common during pregnancy, but the proportion of pregnant women who experience sexual distress is unknown. In non-pregnant samples, sexual distress is associated with lower sexual and relationship satisfaction. To identify the proportion of women experiencing sexual distress during pregnancy and to compare the sexual and relationship satisfaction of women who report sexual distress during pregnancy with that of women without distress. Two-hundred sixty-one pregnant women completed a cross-sectional online survey. Women completed validated measurements of sexual functioning (Female Sexual Function Index; score sexual problem), sexual distress (Female Sexual Distress Scale; score ≥ 15 indicates clinically significant distress), sexual satisfaction (Global Measure of Sexual Satisfaction), and relationship satisfaction (Couples Satisfaction Index). Overall, 42% of women met the clinical cutoff for sexual distress. Of sexually active women (n = 230), 26% reported concurrent sexual problems and distress and 14% reported sexual distress in the absence of sexual problems. Sexual distress and/or problems in sexual functioning were linked to lower sexual and relationship satisfaction compared with pregnant women with lower sexual distress and fewer sexual problems. Sexual distress is common during pregnancy and associated with lower sexual and relationship satisfaction. Health care providers should ask pregnant women about feelings of sexual distress. Identifying pregnant women who experience sexual distress and referring them to appropriate resources could help minimize sexual and relationship problems during pregnancy. Vannier SA, Rosen NO. Sexual Distress and Sexual Problems During Pregnancy: Associations With Sexual and Relationship Satisfaction. J Sex Med 2017;14:387-395. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.
-
Cross-sex genetic correlation does not extend to sexual size dimorphism in spiders
Turk, Eva; Kuntner, Matjaž; Kralj-Fišer, Simona
2018-02-01
Males and females are often subjected to different selection pressures for homologous traits, resulting in sex-specific optima. Because organismal attributes usually share their genetic architectures, sex-specific selection may lead to intralocus sexual conflict. Evolution of sexual dimorphism may resolve this conflict, depending on the degree of cross-sex genetic correlation ( r MF) and the strength of sex-specific selection. In theory, high r MF implies that sexes largely share the genetic base for a given trait and are consequently sexually monomorphic, while low r MF indicates a sex-specific genetic base and sexual dimorphism. Here, we broadly test this hypothesis on three spider species with varying degrees of female-biased sexual size dimorphism, Larinioides sclopetarius (sexual dimorphism index, SDI = 0.85), Nuctenea umbratica (SDI = 0.60), and Zygiella x-notata (SDI = 0.46). We assess r MF via same-sex and opposite-sex heritability estimates. We find moderate body mass heritability but no obvious patterns in sex-specific heritability. Against the prediction, the degree of sexual size dimorphism is unrelated to the relative strength of same-sex versus opposite-sex heritability. Our results do not support the hypothesis that sexual size dimorphism is negatively associated with r MF. We conclude that sex-specific genetic architecture may not be necessary for the evolution of a sexually dimorphic trait.
-
Prenatal undernutrition disrupted the sexual maturation, but not the sexual behavior, in male rats.
Matsuzaki, Toshiya; Munkhzaya, Munkhsaikhan; Tungalagsuvd, Altankhuu; Mayila, Yiliyasi; Iwasa, Takeshi; Yano, Kiyohito; Yanagihara, Rie; Tokui, Takako; Kato, Takeshi; Kuwahara, Akira; Matsui, Sumika; Irahara, Minoru
2017-10-01
Exposure to various stressors, including psychological, metabolic, and immune, in the perinatal period induces long-lasting effects in physiological function and increase the risk of metabolic disorders in later life. In the present study, sexual maturation and sexual behavior were assessed in prenatally undernourished mature male rats. All the pregnant rats were divided into the maternal normal nutrition (mNN) group and the maternal undernutrition (mUN) group. The mUN mothers received 50% of the amount of the daily food intake of the mNN mothers. Preputial separation and sexual behavior were observed in randomly selected pups of the mNN and mUN groups. The body weight of the mothers was significantly lighter in the mUN group than in the mNN group. Similarly, the pups in the mUN group showed a significantly lower body weight than those in the mNN group from postnatal day (PND) 1 to PND 15. The preputial separation day was significantly delayed in the mUN group, compared to the mNN group. Sexual behavior did not show any significant difference between the two groups. These findings indicated that prenatal undernutrition delayed sexual maturation, but did not suppress sexual behavior, in mature male rats.
-
Łaniewska-Trokenheim, Łucja; Olszewska, Magdalena; Miks-Krajnik, Marta; Zadernowska, Anna
2010-08-01
The focus of this study was to monitor the survival of populations and the volatile compound profiles of selected Lactobacillus strains during long-term incubation in milk. The enumeration of cells was determined by both the Direct Epifluorescent Filter Technique using carboxyfluorescein diacetate (CFDA) staining and the plate method. Volatile compounds were analysed by the gas-chromatography technique. All strains exhibited good survival in cultured milks, but Lactobacillus crispatus L800 was the only strain with comparable growth and viability in milk, assessed by plate and epifluorescence methods. The significant differences in cell numbers between plate and microscopic counts were obtained for L. acidophilus strains. The investigated strains exhibited different metabolic profiles. Depending on the strain used, 3 to 8 compounds were produced. The strains produced significantly higher concentrations of acetic acid, compared to other volatiles. Lactobacillus strains differed from one another in number and contents of the volatile compounds.
-
Visiting Entertainment Venues and Sexual Health in China
Li, Li; Wu, Zunyou; Rotheram-Borus, Mary Jane; Guan, Jihui; Yin, Yueping; Detels, Roger; Wu, Sheng; Lee, Sung-Jae; Cao, Haijun; Lin, Chunqing; Rou, Keming; Liu, Zhendong
2008-01-01
Entertainment venues in China are associated with risky sexual behavior. Most previous studies related to entertainment venues in China have focused on sex workers and commercial sex, but this study addressed sexual health in a sample of the general urban population. A randomly selected sample of market vendors (n = 4,510) from an eastern city was recruited and assessed to examine relationships between entertainment venue visits and sexual risk. Both behavioral (self-reports of unprotected se...
-
Sexual Orientation and Spatial Position Effects on Selective Forms of Object Location Memory
Rahman, Qazi; Newland, Cherie; Smyth, Beatrice Mary
2011-01-01
Prior research has demonstrated robust sex and sexual orientation-related differences in object location memory in humans. Here we show that this sexual variation may depend on the spatial position of target objects and the task-specific nature of the spatial array. We tested the recovery of object locations in three object arrays (object…
-
The Rectal Cancer Female Sexuality Score
DEFF Research Database (Denmark)
Thyø, Anne; Emmertsen, Katrine J; Laurberg, Søren
2018-01-01
BACKGROUND: Sexual dysfunction and impaired quality of life is a potential side effect to rectal cancer treatment. OBJECTIVE: The objective of this study was to develop and validate a simple scoring system intended to evaluate sexual function in women treated for rectal cancer. DESIGN......: This is a population-based cross-sectional study. SETTINGS: Female patients diagnosed with rectal cancer between 2001 and 2014 were identified by using the Danish Colorectal Cancer Group's database. Participants filled in the validated Sexual Function Vaginal Changes questionnaire. Women declared to be sexually active...... in the validation group. PATIENTS: Female patients with rectal cancer above the age of 18 who underwent abdominoperineal resection, Hartmann procedure, or total/partial mesorectal excision were selected. MAIN OUTCOME MEASURES: The primary outcome measured was the quality of life that was negatively affected because...
-
Degendering (sexual) violence in intimate relationships
DEFF Research Database (Denmark)
Bertelsen, Eva; Østerby Sørensen, William; Jensen, Mathilde Worch
2018-01-01
Even though Denmark in many respects shows some of the most gender equality rates in the world, the rates of physical and/or sexual violence against women in Denmark are among the highest in Europe. In this article we seek to describe state responses to these figures. We do so by investigating...... the symbolic representations of sexual violence in intimate relationships, framing contemporary political/societal developments of the Danish field of welfare work addressing violence in intimate relationships as well as the dominating knowledge production substantiating these. Theoretically, Slavoj Zizek...... and his concept objective violence inform the paper, in order to analyze authoritative representations of ‘sexual violence in intimate relationships’ in three areas: Danish legislation and legal practices, Danish research on sexual violence, and policy-papers. Thus the Danish Criminal Code, selected...
-
Sexual conflict predicts morphology and behavior in two species of penduline tits
Directory of Open Access Journals (Sweden)
Komdeur Jan
2010-04-01
Full Text Available Abstract Background The evolutionary interests of males and females rarely coincide (sexual conflict, and these conflicting interests influence morphology, behavior and speciation in various organisms. We examined consequences of variation in sexual conflict in two closely-related passerine birds with contrasting breeding systems: the Eurasian penduline tit Remiz pendulinus (EPT exhibiting a highly polygamous breeding system with sexually antagonistic interests over parental care, and the socially monogamous Cape penduline tit Anthoscopus minutus (CPT. We derived four a priori predictions from sexual conflict theory and tested these using data collected in Central Europe (EPT and South Africa (CPT. Firstly, we predicted that EPTs exhibit more sexually dimorphic plumage than CPTs due to more intense sexual selection. Secondly, we expected brighter EPT males to provide less care than duller males. Thirdly, since song is a sexually selected trait in many birds, male EPTs were expected to exhibit more complex songs than CPT males. Finally, intense sexual conflict in EPT was expected to lead to low nest attendance as an indication of sexually antagonistic interests, whereas we expected more cooperation between parents in CPT consistent with their socially monogamous breeding system. Results Consistent with our predictions EPTs exhibited greater sexual dimorphism in plumage and more complex song than CPTs, and brighter EPT males provided less care than duller ones. EPT parents attended the nest less frequently and less simultaneously than CPT parents. Conclusions These results are consistent with sexual conflict theory: species in which sexual conflict is more manifested (EPT exhibited a stronger sexual dimorphism and more elaborated sexually selected traits than species with less intense sexual conflict (CPT. Our results are also consistent with the notion that EPTs attempt to force their partner to work harder as expected under sexual conflict: each
-
Sexual conflict predicts morphology and behavior in two species of penduline tits.
van Dijk, René E; Pogány, Akos; Komdeur, Jan; Lloyd, Penn; Székely, Tamás
2010-04-23
The evolutionary interests of males and females rarely coincide (sexual conflict), and these conflicting interests influence morphology, behavior and speciation in various organisms. We examined consequences of variation in sexual conflict in two closely-related passerine birds with contrasting breeding systems: the Eurasian penduline tit Remiz pendulinus (EPT) exhibiting a highly polygamous breeding system with sexually antagonistic interests over parental care, and the socially monogamous Cape penduline tit Anthoscopus minutus (CPT). We derived four a priori predictions from sexual conflict theory and tested these using data collected in Central Europe (EPT) and South Africa (CPT). Firstly, we predicted that EPTs exhibit more sexually dimorphic plumage than CPTs due to more intense sexual selection. Secondly, we expected brighter EPT males to provide less care than duller males. Thirdly, since song is a sexually selected trait in many birds, male EPTs were expected to exhibit more complex songs than CPT males. Finally, intense sexual conflict in EPT was expected to lead to low nest attendance as an indication of sexually antagonistic interests, whereas we expected more cooperation between parents in CPT consistent with their socially monogamous breeding system. Consistent with our predictions EPTs exhibited greater sexual dimorphism in plumage and more complex song than CPTs, and brighter EPT males provided less care than duller ones. EPT parents attended the nest less frequently and less simultaneously than CPT parents. These results are consistent with sexual conflict theory: species in which sexual conflict is more manifested (EPT) exhibited a stronger sexual dimorphism and more elaborated sexually selected traits than species with less intense sexual conflict (CPT). Our results are also consistent with the notion that EPTs attempt to force their partner to work harder as expected under sexual conflict: each member of the breeding pair attempts to shift the
-
Selection gradients, the opportunity for selection, and the coefficient of determination.
Moorad, Jacob A; Wade, Michael J
2013-03-01
Abstract We derive the relationship between R(2) (the coefficient of determination), selection gradients, and the opportunity for selection for univariate and multivariate cases. Our main result is to show that the portion of the opportunity for selection that is caused by variation for any trait is equal to the product of its selection gradient and its selection differential. This relationship is a corollary of the first and second fundamental theorems of natural selection, and it permits one to investigate the portions of the total opportunity for selection that are involved in directional selection, stabilizing (and diversifying) selection, and correlational selection, which is important to morphological integration. It also allows one to determine the fraction of fitness variation not explained by variation in measured phenotypes and therefore attributable to random (or, at least, unknown) influences. We apply our methods to a human data set to show how sex-specific mating success as a component of fitness variance can be decoupled from that owing to prereproductive mortality. By quantifying linear sources of sexual selection and quadratic sources of sexual selection, we illustrate that the former is stronger in males, while the latter is stronger in females.
-
Original article Sexual self-esteem and sexual needs of young adults with cerebral palsy
Directory of Open Access Journals (Sweden)
Klaudia Czapla
2014-10-01
Full Text Available Background Sexuality is an important part of human existence, irrespective of race, religion or level of physical fitness. It can, however, be treated and exhibited by individuals in very different ways. The place of sexuality in a person’s life, and in the way it is materialised, is determined by a number of biopsychosocial factors. For some, the presence of these factors and their influence is not a matter of choice. They may arise as a consequence of the psychophysical condition of their organism. People with motor disabilities undoubtedly belong to this group. Participants and procedure The study was carried out in Poland on a group of 61 people with roughly equal proportions of men and women. Subject selection was non-random; every subject was diagnosed with cerebral palsy (CP and was aged between 15 and 25. All of the subjects had normal levels of intelligence. Two methods were used in the study: Sexual Self-esteem Scale and Sexual Needs Scale. Results The results in terms of sexual self-esteem and sexual needs allowed two different subgroups of subjects to be distinguished (H – with high scores; L – with low scores. The analysis of significance levels of the differences in terms of sexual self-esteem and sexual needs between subgroups H and L confirmed the clear distinction between each of the subgroups’ clinical pictures (p < .001 in 20 out of 21 of the analysed aspects. Falling in love was the only matter that did not differentiate the subgroups. Conclusions There is a clear polarization of the results. Only 1/3 of the respondents had high sexual self-esteem and sexual needs. The remaining 2/3 reported having a rather low sexual self-esteem and low levels of needs with regards to their own sexuality. It needs to be stressed that CP-affected youth, similarly to their peers, may need support in discovering their sexuality and satisfying their sexual needs (2/3 of the respondents. The specifics of the range of support should
-
Adeniyi, W. O.; Okewole, J. O.
2014-01-01
The study examined the influence of knowledge and awareness of sexually transmitted diseases on change in sexual behaviour of fresh undergraduates with a view to providing useful suggestions for positive sexual behaviour of adolescents. The study adopted the descriptive survey design. A sample of 600 fresh undergraduates was selected from the…
-
Soler, J J; Moreno, J
2012-08-01
Wallace proposed in 1868 that natural rather than sexual selection could explain the striking differences in avian plumage dichromatism. Thus, he predicted that nesting habits, through their association with nest predation, could drive changes in sexual dichromatism by enabling females in cavity nesters to become as conspicuous as males, whereas Darwin (1871, The Descent of Man and Selection in Relation to Sex, John Murray, London) argued that sexual selection was the sole explanation for dichromatism. Sexual dichromatism is currently used as indicating the strength of sexual selection, and therefore testing Wallace's claim with modern phylogentically controlled methodologies is of prime interest for comparing the roles of natural and sexual selection in affecting the evolution of avian coloration. Here, we have related information on nest attendance, sexual dichromatism and nesting habits (open and cavity nesting) to male and female plumage conspicuousness in European passerines. Nest incubation attendance does not explain male or female plumage conspicuousness but nest type does. Moreover, although females of monochromatic and cavity nesting species are more conspicuous than females of other species, males of monochromatic and open nesting species are those with more cryptic plumage. Finally, analyses of character evolution suggest that changes in nesting habits influence the probability of changes in both dichromatism and plumage conspicuousness of males but do not significantly affect those in females. These results strongly suggest a role of nesting habits in the evolution of plumage conspicuousness of males, and a role for sexual selection also in females, both factors affecting the evolution of sexual dichromatism. We discuss our findings in relation to the debate that Darwin and Wallace maintained more than one century ago on the importance of natural and sexual selection in driving the evolution of plumage conspicuousness and sexual dichromatism in birds
-
Adolescent Sexual Decision-Making: An Integrative Review.
Hulton, Linda J.
2001-10-03
PURPOSE: The purpose of this integrative review was to summarize the present literature to identify factors associated with adolescent sexual decision-making. Thirty-eight salient research studies were selected as a basis of this review from the databases of Medline, CINAHL, and Psychinfo using the Cooper methodology. CONCLUSIONS: Two categories of decision-making were identified: 1) The research on factors related to the decisions that adolescents make to become sexually active or to abstain from sexual activity; 2) The research on factors related to contraceptive decision-making. The most consistent findings were that the factors of gender differences, cognitive development, perception of benefits, parental influences, social influences, and sexual knowledge were important variables in the decision-making processes of adolescents. IMPLICATIONS: Practice implications for nursing suggest that clinicians should assess adolescent sexual decision-making in greater detail and address the social and psychological context in which sexual experiences occur. Nurses must be aware of the differences between adolescent and adult decision-making processes and incorporate knowledge of growth and development into intervention strategies. Moreover, to the degree that adolescent sexual decision-making proves to be less than rational, interventions designed to improve competent sexual decision-making are needed.
-
Directory of Open Access Journals (Sweden)
Jensen Just
2002-05-01
Full Text Available Abstract In this paper, we consider selection based on the best predictor of animal additive genetic values in Gaussian linear mixed models, threshold models, Poisson mixed models, and log normal frailty models for survival data (including models with time-dependent covariates with associated fixed or random effects. In the different models, expressions are given (when these can be found – otherwise unbiased estimates are given for prediction error variance, accuracy of selection and expected response to selection on the additive genetic scale and on the observed scale. The expressions given for non Gaussian traits are generalisations of the well-known formulas for Gaussian traits – and reflect, for Poisson mixed models and frailty models for survival data, the hierarchal structure of the models. In general the ratio of the additive genetic variance to the total variance in the Gaussian part of the model (heritability on the normally distributed level of the model or a generalised version of heritability plays a central role in these formulas.
-
Persistent sexual dysfunction after early exposure to SSRIs
DEFF Research Database (Denmark)
Simonsen, Anders Lykkemark; Danborg, Pia Brandt; Gøtzsche, Peter Christian
2016-01-01
BACKGROUND: Sexual dysfunction is a common adverse effect of selective serotonin reuptake inhibitors (SSRIs) and there is a concern that the sexual harms might persist after discontinuation of therapy. OBJECTIVE: To assess whether the use of SSRIs in animals can lead to persistent sexual...... dysfunction. METHODS: Systematic review of animal studies measuring sexual behaviour after end of treatment with SSRIs or serotonin norepinephrine reuptake inhibitors. DATA SOURCES: We searched PubMed and EMBASE. RESULTS: We included 14 studies. The general quality of the studies was poor. Only four studies.......74; 95% CI = 0.60-0.92) and no ejaculation behaviour (RR = 0.49, 95% CI = 0.24-1.00). CONCLUSION: Our results showed substantial and lasting effects on sexual behaviour in rats after exposure to an SSRI early in life on important sexual outcomes....
-
The impact of mental illness on sexual dysfunction.
Zemishlany, Zvi; Weizman, Abraham
2008-01-01
Sexual dysfunction is prevalent among psychiatric patients and may be related to both the psychopathology and the pharmacotherapy. The negative symptoms of schizophrenia limit the capability for interpersonal and sexual relationships. The first-generation antipsychotics cause further deterioration in erectile and orgasmic function. Due to their weak antagonistic activity at D2 receptors, second-generation antipsychotics are associated with fewer sexual side effects, and thus may provide an option for schizophrenia patients with sexual dysfunction. Depression and anxiety are a cause for sexual dysfunction that may be aggravated by antidepressants, especially selective serotonin reuptake inhibitors (SSRIs). SSRI-induced sexual dysfunction may be overcome by lowering doses, switching to an antidepressant with low propensity to cause sexual dysfunction (bupropion, mirtazapine, nefazodone, reboxetine), addition of 5HT2 antagonists (mirtazapine, mianserin) or coadministration of 5-phosphodiesterase inhibitors. Eating disorders and personality disorders, mainly borderline personality disorder, are also associated with sexual dysfunction. Sexual dysfunction in these cases stems from impaired interpersonal relationships and may respond to adequate psychosexual therapy. It is mandatory to identify the specific sexual dysfunction and to treat the patients according to his/her individual psychopathology, current pharmacotherapy and interpersonal relationships.
-
Regret Expression and Social Learning Increases Delay to Sexual Gratification.
Directory of Open Access Journals (Sweden)
Amanda J Quisenberry
Full Text Available Modification and prevention of risky sexual behavior is important to individuals' health and public health policy. This study employed a novel sexual discounting task to elucidate the effects of social learning and regret expression on delay to sexual gratification in a behavioral task.Amazon Mechanical Turk Workers were assigned to hear one of three scenarios about a friend who engages in similar sexual behavior. The scenarios included a positive health consequence, a negative health consequence or a negative health consequence with the expression of regret. After reading one scenario, participants were asked to select from 60 images, those with whom they would have casual sex. Of the selected images, participants chose one image each for the person they most and least want to have sex with and person most and least likely to have a sexually transmitted infection. They then answered questions about engaging in unprotected sex now or waiting some delay for condom-protected sex in each partner condition.Results indicate that the negative health outcome scenario with regret expression resulted in delayed sexual gratification in the most attractive and least STI partner conditions, whereas in the least attractive and most STI partner conditions the negative health outcome with and without regret resulted in delayed sexual gratification.Results suggest that the sexual discounting task is a relevant laboratory measure and the framing of information to include regret expression may be relevant for prevention of risky sexual behavior.
-
Sexual conflict arising from extrapair matings in birds.
Chaine, Alexis S; Montgomerie, Robert; Lyon, Bruce E
2015-01-20
The discovery that extrapair copulation (EPC) and extrapair paternity (EPP) are common in birds led to a paradigm shift in our understanding of the evolution of mating systems. The prevalence of extrapair matings in pair-bonded species sets the stage for sexual conflict, and a recent focus has been to consider how this conflict can shape variation in extrapair mating rates. Here, we invert the causal arrow and consider the consequences of extrapair matings for sexual conflict. Extrapair matings shift sexual conflict from a simple two-player (male vs. female) game to a game with three or more players, the nature of which we illustrate with simple diagrams that highlight the net costs and benefits of extrapair matings to each player. This approach helps identify the sorts of traits that might be under selection because of sexual conflict. Whether EPP is driven primarily by the extrapair male or the within-pair female profoundly influences which players are in conflict, but the overall pattern of conflict varies little among different mating systems. Different aspects of conflict are manifest at different stages of the breeding cycle and can be profitably considered as distinct episodes of selection caused by conflict. This perspective is illuminating both because conflict between specific players can change across episodes and because the traits that evolve to mediate conflict likely differ between episodes. Although EPP clearly leads to sexual conflict, we suggest that the link between sexual conflict and multiple paternity might be usefully understood by examining how deviations from lifetime sexual monogamy influence sexual conflict. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.
-
Molina, R; Araa, S; Ibazeta, G; Jordan, P; Lagos, E
1987-01-01
A survey of knowledge, attitude, and practices regarding human reproduction and sexuality was undertaken in 2 groups of secondary school students in Chile to assess whether greater knowledge of reproduction and sexuality is associated with greater permissiveness and earlier initiation of sexual activity. Students in 2 public schools, 1 coeducational and 1 for female students only, were of lower middle class background, while students at the coeducational private school were of higher socioeconomic status. An anonymous, semiclosed questionnaire was administered to students in the 3 schools. The schools were selected because their directors agreed to permit the study. 14.8% of the 351 public school students were aged 14 or under and 77.8% were 15-18, while 99.5% of the 197 private school students were aged 15-18. The students' levels of knowledge of human reproduction and sexuality were measured through direct personal assessments by the students themselves and through 21 questions to confirm the assessments. At least 93% of students in all schools said their level of knowledge was medium or high, but the test indicated that only 64% of public school students and 75% of private school students actually had medium or high levels of knowledge. 45.9% of private and 27.9% of public school students felt the information they received from their schools about sexuality was adequate, while 41.9% of private and 60.9% of public school students felt it was insufficient. There were no significant differences in the opinions of the 2 groups of students concerning premarital sex, but the reasons given by the private school students to explain their attitudes expressed a greater sense of commitment to the partner, while those of the public school students tended to be more functional. Among public school students, 38.7% of males and 9.7% of females reported having had sexual relations, while among private school students, 17.7% of males and 4.4% of females reported having done so
-
Timmerman, M. C.
2004-01-01
Objective: To explore the impact of the school climate on adolescents' reporting of sexual harassment. Design: A quantitative survey among students in their 4th year of secondary education. Setting: Questionnaires were completed in a class setting. Method: An a-select sampling strategy was used to select 2808 students in 22 schools. Results:…
-
Garduño-Gutiérrez, René; León-Olea, Martha; Rodríguez-Manzo, Gabriela
2013-11-01
Male rats allowed to copulate until reaching sexual exhaustion exhibit a long-lasting sexual behavior inhibition (around 72 h) that can be reversed by systemic opioid receptor antagonist administration. Copulation activates the mesolimbic dopaminergic system (MLS) and promotes endogenous opioid release. In addition, endogenous opioids, acting at the ventral tegmental area (VTA), modulate the activity of the MLS. We hypothesized that endogenous opioids participate in the sexual exhaustion phenomenon by interacting with VTA opioid receptors and consequently, its reversal by opioid antagonists could be exerted at those receptors. In this study we determined the effects of intra-VTA infusion of different doses of the non-specific opioid receptor antagonist naltrexone (0.1-1.0 μg/rat) on the already established sexual behavior inhibition of sexually exhausted male rats. To elucidate the possible involvement of VTA δ-opioid receptors in the naltrexone-mediated reversal of sexual exhaustion, the effects of different doses of the selective δ-opioid receptor antagonist, naltrindole (0.03-1.0 μg/rat) were also tested. Results showed that intra-VTA injection of 0.3 μg naltrexone reversed the sexual inhibition of sexually exhausted rats, evidenced by an increased percentage of animals capable of showing two successive ejaculations. Intra-VTA infused naltrindole did not reverse sexual exhaustion at any dose. It is concluded that the MLS is involved in the reversal of sexual exhaustion induced by systemic naltrexone, and that μ-, but not δ-opioid receptors participate in this effect. Intra-VTA naltrexone infusion to sexually experienced male rats had an inhibitory effect on sexual activity. The opposite effects of intra-VTA naltrexone on male rat sexual behavior expression of sexually experienced and sexually exhausted rats is discussed. Copyright © 2013 Elsevier B.V. All rights reserved.
-
D. Max Smith; Deborah M. Finch; David L. Hawksworth
2009-01-01
Despite widespread efforts to avert wildfire by reducing the density of flammable vegetation, little is known about the effects of this practice on the reproductive biology of forest birds. We examined nest-site selection and nest survival of the Black-chinned Hummingbird (Archilochus alexandri) in New Mexico riparian forests treated or not for fuel...
-
The Shadow of Silence on the Sexual Rights of Married Iranian Women
Directory of Open Access Journals (Sweden)
Roksana Janghorban
2015-01-01
Full Text Available There has been a recent shift in the field of sexual health, representing a move away from biomedical concerns to sexual rights frameworks. However, few studies on sexuality are based on a rights framework. The unspoken nature of sexuality in Iranian culture has led to a lack of national studies on the topic. The objective of this study was to explore the perceptions and experiences of married Iranian women on sexual rights in their sexual relationships. In this grounded theory study, 37 participants (25 married women, 5 husbands, and 7 midwives were selected. Data were collected through in-depth interviews and analyzed through open, axial, and selective coding using MAXQDA software version 2007. The analysis revealed the core category of “sexual interaction in the shadow of silence.” The interrelated categories subsumed under the core category included adopting a strategy of silence, trying to negotiate sex, seeking help, and sexual adjustment. The silence originating from women’s interactions with their families and society, from girlhood to womanhood, was identified as the core concept in Iranian women’s experiences of sexual rights. A focus on husbands’ roles seems salient because they can direct or alter some learned feminine roles, especially silence regarding sexual matters, which then affects the realization of women’s sexual rights.
-
Rajabizadeh, Ghodratolah; Yazdanpanah, Fatemeh; Ramezani, Mohammad Arash
2017-01-01
Background The present study was conducted with the aim of designing a causal model for the evaluation of sexual dysfunctions based on the variables of methadone dosage and sexual self-concept among individuals undergoing methadone maintenance treatment (MMT). Methods The study population of the present study consisted of married men of 20 to 45 years of age with sexual ýrelations and undergoing MMT for a minimum of 8 weeks referring to all MMT clinics of Kerman, Iran, in ýý2015-2016. ýThe subjects were selected through multi-stage cluster sampling (n = 250). Data were collected using the General Health Questionnaire (GHQ-28), Multi-Dimensional Sexual Self-concept Questionnaire (MSSQ), and Internal Index for Erectile Function (IIEF). Data were analyzed using path analysis method and Pearson correlation coefficient. The suggested model was evaluated using structural equation model (SEM), and indirect relationships were assessed using Bootstrap method. Findings The suggested model showed acceptable fitness with the data, and all routes, except methadone use route, to sexual function were significant. The result of the multiple ýindirect route showed that sexual function had a significant relationship with methadone use through ýsexual self-concept. In total, 60% of variance in sexual dysfunction was explained using the variables of the suggested model. Conclusion Further studies are suggested to be conducted regarding psychological factors effective on the sexual dysfunctions among individuals undergoing MMT, such as sexual self-concept. Moreover, more detailed evaluation of each subscale of positive and negative sexual self-concept is recommended to assess the psychological causes of sexual dysfunctions in these individuals and design psychological, behavioral, and cognitive-behavioral treatment interventions for them. PMID:29299211
-
Rajabizadeh, Ghodratolah; Yazdanpanah, Fatemeh; Ramezani, Mohammad Arash
2017-04-01
The present study was conducted with the aim of designing a causal model for the evaluation of sexual dysfunctions based on the variables of methadone dosage and sexual self-concept among individuals undergoing methadone maintenance treatment (MMT). The study population of the present study consisted of married men of 20 to 45 years of age with sexual ýrelations and undergoing MMT for a minimum of 8 weeks referring to all MMT clinics of Kerman, Iran, in ýý2015-2016. ýThe subjects were selected through multi-stage cluster sampling (n = 250). Data were collected using the General Health Questionnaire (GHQ-28), Multi-Dimensional Sexual Self-concept Questionnaire (MSSQ), and Internal Index for Erectile Function (IIEF). Data were analyzed using path analysis method and Pearson correlation coefficient. The suggested model was evaluated using structural equation model (SEM), and indirect relationships were assessed using Bootstrap method. The suggested model showed acceptable fitness with the data, and all routes, except methadone use route, to sexual function were significant. The result of the multiple ýindirect route showed that sexual function had a significant relationship with methadone use through ýsexual self-concept. In total, 60% of variance in sexual dysfunction was explained using the variables of the suggested model. Further studies are suggested to be conducted regarding psychological factors effective on the sexual dysfunctions among individuals undergoing MMT, such as sexual self-concept. Moreover, more detailed evaluation of each subscale of positive and negative sexual self-concept is recommended to assess the psychological causes of sexual dysfunctions in these individuals and design psychological, behavioral, and cognitive-behavioral treatment interventions for them.
-
Applied survival analysis using R
Moore, Dirk F
2016-01-01
Applied Survival Analysis Using R covers the main principles of survival analysis, gives examples of how it is applied, and teaches how to put those principles to use to analyze data using R as a vehicle. Survival data, where the primary outcome is time to a specific event, arise in many areas of biomedical research, including clinical trials, epidemiological studies, and studies of animals. Many survival methods are extensions of techniques used in linear regression and categorical data, while other aspects of this field are unique to survival data. This text employs numerous actual examples to illustrate survival curve estimation, comparison of survivals of different groups, proper accounting for censoring and truncation, model variable selection, and residual analysis. Because explaining survival analysis requires more advanced mathematics than many other statistical topics, this book is organized with basic concepts and most frequently used procedures covered in earlier chapters, with more advanced topics...
-
Rethinking our assumptions about the evolution of bird song and other sexually dimorphic signals
Directory of Open Access Journals (Sweden)
J. Jordan Price
2015-04-01
Full Text Available Bird song is often cited as a classic example of a sexually-selected ornament, in part because historically it has been considered a primarily male trait. Recent evidence that females also sing in many songbird species and that sexual dimorphism in song is often the result of losses in females rather than gains in males therefore appears to challenge our understanding of the evolution of bird song through sexual selection. Here I propose that these new findings do not necessarily contradict previous research, but rather they disagree with some of our assumptions about the evolution of sexual dimorphisms in general and female song in particular. These include misconceptions that current patterns of elaboration and diversity in each sex reflect past rates of change and that levels of sexual dimorphism necessarily reflect levels of sexual selection. Using New World blackbirds (Icteridae as an example, I critically evaluate these past assumptions in light of new phylogenetic evidence. Understanding the mechanisms underlying such sexually dimorphic traits requires a clear understanding of their evolutionary histories. Only then can we begin to ask the right questions.
-
Hald, Gert Martin; Stulhofer, Aleksandar; Lange, Theis
2018-03-01
Investigations of patterns of sexual arousal to certain groups of sexually explicit media (SEM) in the general population in non-laboratory settings are rare. Such knowledge could be important to understand more about the relative specificity of sexual arousal in different SEM users. (i) To investigate whether sexual arousal to non-mainstream vs mainstream SEM contents could be categorized across gender and sexual orientation, (ii) to compare levels of SEM-induced sexual arousal, sexual satisfaction, and self-evaluated sexual interests and fantasies between non-mainstream and mainstream SEM groups, and (iii) to explore the validity and predictive accuracy of the Non-Mainstream Pornography Arousal Scale (NPAS). Online cross-sectional survey of 2,035 regular SEM users in Croatia. Patterns of sexual arousal to 27 different SEM themes, sexual satisfaction, and self-evaluations of sexual interests and sexual fantasies. Groups characterized by sexual arousal to non-mainstream SEM could be identified across gender and sexual orientation. These non-mainstream SEM groups reported more SEM use and higher average levels of sexual arousal across the 27 SEM themes assessed compared with mainstream SEM groups. Only few differences were found between non-mainstream and mainstream SEM groups in self-evaluative judgements of sexual interests, sexual fantasies, and sexual satisfaction. The internal validity and predictive accuracy of the NPAS was good across most user groups investigated. The findings suggest that in classified non-mainstream SEM groups, patterns of sexual arousal might be less fixated and category specific than previously assumed. Further, these groups are not more judgmental of their SEM-related sexual arousal patterns than groups characterized by patterns of sexual arousal to more mainstream SEM content. Moreover, accurate identification of non-mainstream SEM group membership is generally possible across gender and sexual orientation using the NPAS. Hald GM
-
The sex life of women surviving breast cancer.
Ghizzani, Anna; Bruni, Simone; Luisi, Stefano
2018-04-27
The diagnosis of breast cancer elicits diverse emotional responses in patients and partners. Surviving cancer has raised new needs and caretakers must understand the medical and psychological latent effects of oncology therapy. Improving patients' well-being is crucial as 19 million survivors are expected in the next decade in the United States alone. In general, sexuality contributes to one's well-being but when it is disrupted by the occurrence of cancer, women withdraw emotionally, no longer feel desirable due to esthetic damage, and become overwhelmed by the thought of sex. Alopecia and mastectomy elicit feelings of unattractiveness affecting even some women with nipple sparing mastectomy. Couples who share the psychological distress of experiencing cancer should be logically included in survivorship interventions. Hence, any support offered to the couple improves their ability to cope significantly. Treatments causing premature ovarian failure as well as adjuvant endocrine treatments deepen the effects of hypo-estrogenism on the genital modifications of arousal. Sexual rehabilitation with vaginal dilators and sensate focus exercises help to lessen pain, and reduce the couple's anxiety toward sex. In conclusion, caregivers must realize that surviving women are often reluctant to voice their needs, thus, efficient interventions must be available to everyone.
-
Sexual Narcissism and the Perpetration of Sexual Aggression
McNulty, James K.
2014-01-01
Despite indirect evidence linking narcissism to sexual aggression, studies directly examining this relationship have yielded inconsistent results. Likely contributing to such inconsistencies, prior research has used global measures of narcissism not sensitive to whether the components of narcissism are activated in sexual versus non-sexual domains. The current research avoided such problems by using a measure of sexual narcissism to predict sexual aggression. In a sample of 299 men and women, Study 1 validated the Sexual Narcissism Scale, a new sexuality research instrument with four subscales—Sexual Exploitation, Sexual Entitlement, Low Sexual Empathy, and Sexual Skill. Then, in a sample of 378 men, Study 2 demonstrated that sexual narcissism was associated with reports of the frequency of sexual aggression, three specific types of sexual aggression (unwanted sexual contact, sexual coercion, and attempted/completed rape), and the likelihood of future sexual aggression. Notably, global narcissism was unrelated to all indices of sexual aggression when sexual narcissism was controlled. That sexual narcissism outperformed global assessments of narcissism to account for variance in sexual aggression suggests that future research may benefit by examining whether sexual narcissism and other sexual-situation-specific measurements of personality can similarly provide a more valid test of the association between personality and other sexual behaviors and outcomes (e.g., contraceptive use, infidelity, sexual satisfaction). PMID:19130204
-
Sexual narcissism and the perpetration of sexual aggression.
Widman, Laura; McNulty, James K
2010-08-01
Despite indirect evidence linking narcissism to sexual aggression, studies directly examining this relationship have yielded inconsistent results. Likely contributing to such inconsistencies, prior research has used global measures of narcissism not sensitive to whether the components of narcissism are activated in sexual versus non-sexual domains. The current research avoided such problems by using a measure of sexual narcissism to predict sexual aggression. In a sample of 299 men and women, Study 1 validated the Sexual Narcissism Scale, a new sexuality research instrument with four subscales-Sexual Exploitation, Sexual Entitlement, Low Sexual Empathy, and Sexual Skill. Then, in a sample of 378 men, Study 2 demonstrated that sexual narcissism was associated with reports of the frequency of sexual aggression, three specific types of sexual aggression (unwanted sexual contact, sexual coercion, and attempted/completed rape), and the likelihood of future sexual aggression. Notably, global narcissism was unrelated to all indices of sexual aggression when sexual narcissism was controlled. That sexual narcissism outperformed global assessments of narcissism to account for variance in sexual aggression suggests that future research may benefit by examining whether sexual narcissism and other sexual-situation-specific measurements of personality can similarly provide a more valid test of the association between personality and other sexual behaviors and outcomes (e.g., contraceptive use, infidelity, sexual satisfaction).
-
DeLuzio, Matthew R; Moores, Craig; Dhamija, Ankit; Wang, Zuoheng; Cha, Charles; Boffa, Daniel J; Detterbeck, Frank C; Kim, Anthony W
2015-01-01
To conduct a systematic review of the existing literature regarding surgical therapy for oligometastatic lung cancer to the pancreas. Data was collected on patients with singular pancreatic metastases from lung cancer from papers published between January 1970 and June 2014. This was performed following the Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) guidelines. Kaplan-Meier and Cox Regression analyses were then used to determine and compare survival. There were 27 papers that fulfilled the search criteria, from which data on 32 patients was collected. Non-small cell lung cancer (NSCLC) was the most prevalent type of primary lung malignancy, and metachronous presentations of metastases were most common. Lesions were most frequently located in the pancreatic head and consequently the most common curative intent metastasectomy was pancreaticoduodenectomy. There was a statistically significant survival benefit for patients whose metastasis were discovered incidentally by surveillance CT as opposed to those whose metastasis were discovered during a work up for new somatic complaints (p = 0.024). The overall median survival for patients undergoing curative intent resection was 29 months, with 2-year and 5-year survivals of 65% and 21% respectively. Palliative surgery or medical only management was associated with a median survival of 8 months and 2-year and 5-year survivals of 25% and 8% respectively. Curative intent resection of isolated pancreatic metastasis from lung cancer may be beneficial in a select group of patients. Copyright © 2015 IAP and EPC. Published by Elsevier B.V. All rights reserved.
-
Niehaus, Ashley F; Jackson, Joan; Davies, Stephanie
2010-12-01
Childhood sexual trauma has been demonstrated to increase survivors' risk for engaging in unrestricted sexual behaviors and experiencing adolescent sexual assault. The current study used the sexual self-schema construct to examine cognitive representations of sexuality that might drive these behavioral patterns. In Study 1 (N = 774), we attempted to improve the content validity of the Sexual Self Schema Scale for child sexual abuse (CSA) survivors, introducing a fourth sexual self-schema factor titled the "immoral/irresponsible" factor. In Study 2 (N = 1150), the potential differences in sexual self-views, as assessed by the four sexual self-schema factors, between CSA survivors and non-victims were explored. In addition, Study 2 evaluated how these sexual self-schema differences may contribute to participation in unrestricted sexual behaviors and risk for sexual assault in adolescence. Results indicated that a history of CSA impacted the way women viewed themselves as a sexual person on each of the four factors. CSA survivors were found to view themselves as more open and possessing more immoral/irresponsible cognitions about sexuality as compared to women who did not have a CSA history. In addition, the CSA survivors endorsed less embarrassment and passionate/romantic views of their sexual selves. The interaction of CSA severity and the sexual self-schemas explained variance in adolescent sexual assault experiences above and beyond the severity of CSA history and participation in risky sexual behaviors. The findings suggest that sexual self-views may serve to moderate the relationship between CSA and adolescent sexual assault. Implications of these findings and directions for future research are discussed.
-
The human sexual response cycle: brain imaging evidence linking sex to other pleasures.
Georgiadis, J R; Kringelbach, M L
2012-07-01
Sexual behavior is critical to species survival, yet comparatively little is known about the neural mechanisms in the human brain. Here we systematically review the existing human brain imaging literature on sexual behavior and show that the functional neuroanatomy of sexual behavior is comparable to that involved in processing other rewarding stimuli. Sexual behavior clearly follows the established principles and phases for wanting, liking and satiety involved in the pleasure cycle of other rewards. The studies have uncovered the brain networks involved in sexual wanting or motivation/anticipation, as well as sexual liking or arousal/consummation, while there is very little data on sexual satiety or post-orgasmic refractory period. Human sexual behavior also interacts with other pleasures, most notably social interaction and high arousal states. We discuss the changes in the underlying brain networks supporting sexual behavior in the context of the pleasure cycle, the changes to this cycle over the individual's life-time and the interactions between them. Overall, it is clear from the data that the functional neuroanatomy of sex is very similar to that of other pleasures and that it is unlikely that there is anything special about the brain mechanisms and networks underlying sex. Copyright © 2012 Elsevier Ltd. All rights reserved.
-
Sexual media exposure, sexual behavior, and sexual violence victimization in adolescence.
Ybarra, Michele L; Strasburger, Victor C; Mitchell, Kimberly J
2014-11-01
Emerging research suggests sexual media affects sexual behavior, but most studies are based on regional samples and few include measures of newer mediums. Furthermore, little is known about how sexual media relates to sexual violence victimization. Data are from 1058 youth 14 to 21 years of age in the national, online Growing up with Media study. Forty-seven percent reported that many or almost all/all of at least one type of media they consumed depicted sexual situations. Exposure to sexual media in television and movies, and music was greater than online and in games. All other things equal, more frequent exposure to sexual media was related to ever having had sex, coercive sex victimization, and attempted/completed rape but not risky sexual behavior. Longer standing mediums such as television and movies appear to be associated with greater amounts of sexual media consumption than newer ones, such as the Internet. A nuanced view of how sexual media content may and may not be affecting today's youth is needed. © The Author(s) 2014.
-
Olver, Mark E; Sowden, Justina N; Kingston, Drew A; Nicholaichuk, Terry P; Gordon, Audrey; Beggs Christofferson, Sarah M; Wong, Stephen C P
2018-04-01
The present study examined the predictive properties of Violence Risk Scale-Sexual Offender version (VRS-SO) risk and change scores among Aboriginal and non-Aboriginal sexual offenders in a combined sample of 1,063 Canadian federally incarcerated men. All men participated in sexual offender treatment programming through the Correctional Service of Canada (CSC) at sites across its five regions. The Static-99R was also examined for comparison purposes. In total, 393 of the men were identified as Aboriginal (i.e., First Nations, Métis, Circumpolar) while 670 were non-Aboriginal and primarily White. Aboriginal men scored significantly higher on the Static-99R and VRS-SO and had higher rates of sexual and violent recidivism; however, there were no significant differences between Aboriginal and non-Aboriginal groups on treatment change with both groups demonstrating close to a half-standard deviation of change pre and post treatment. VRS-SO risk and change scores significantly predicted sexual and violent recidivism over fixed 5- and 10-year follow-ups for both racial/ancestral groups. Cox regression survival analyses also demonstrated positive treatment changes to be significantly associated with reductions in sexual and violent recidivism among Aboriginal and non-Aboriginal men after controlling baseline risk. A series of follow-up Cox regression analyses demonstrated that risk and change score information accounted for much of the observed differences between Aboriginal and non-Aboriginal men in rates of sexual recidivism; however, marked group differences persisted in rates of general violent recidivism even after controlling for these covariates. The results support the predictive properties of VRS-SO risk and change scores with treated Canadian Aboriginal sexual offenders.
-
Brassard, Audrey; Dupuy, Emmanuelle; Bergeron, Sophie; Shaver, Phillip R
2015-01-01
We examined the potential role of three mediators--sexual self-esteem, sexual anxiety, and sexual assertiveness--of the association between romantic attachment insecurities (anxiety and avoidance) and two aspects of women's sexual functioning: sexual function and sexual satisfaction. A sample of 556 women aged 18 to 30 agreed to complete an online series of validated questionnaires assessing attachment insecurities and several aspects of sexual functioning. Lower sexual self-esteem and higher sexual anxiety mediated the associations between attachment anxiety and lower sexual function and satisfaction. Lower sexual self-esteem and higher sexual anxiety also partially mediated the links between attachment-related avoidance and the two sexual functioning variables. Sexual assertiveness, however, did not mediate these associations. A significant interaction between attachment anxiety and avoidance was also found to predict sexual satisfaction, with women high in avoidance and low in anxiety being the least satisfied. Results are discussed in terms of theoretical and clinical implications.
-
Conceptual model of male military sexual trauma.
Elder, William B; Domino, Jessica L; Rentz, Timothy O; Mata-Galán, Emma L
2017-08-01
Male sexual trauma is understudied, leaving much to be known about the unique mental health needs of male survivors. This study examined veteran men's perceptions of the effects of military sexual trauma. Military sexual trauma was defined as physically forced, verbally coerced, or substance-incapacitated acts experienced during military service. Interviews were conducted with 21 male veterans who reported experiencing military sexual trauma. Data were drawn together using a grounded theory methodology. Three categories emerged from data analysis, including (a) types of military sexual trauma (being touched in a sexual way against their will [N = 18]; sexual remarks directed at them [N = 15]; being physically forced to have sex [N = 13]); (b) negative life effects (difficulty trusting others [N = 18]; fear of abandonment [N = 17]; substance use [N = 13]; fear of interpersonal violence [N = 12]; conduct and vocational problems [N = 11]; irritability/aggression [N = 8]; insecurity about sexual performance [N = 8]; difficulty managing anger [N = 8]); and (c) posttraumatic growth (N = 15). Results from this study suggest sexual trauma in the military context may affect systems of self-organization, specifically problems in affective, self-concept, and relational domains, similar to symptoms of those who have experienced prolonged traumatic stressors. This model can be used by clinicians to select treatments that specifically target these symptoms and promote posttraumatic growth. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
-
A lover or a fighter? Opposing sexual selection pressures on men's vocal pitch and facial hair.
Saxton, Tamsin K; Mackey, Lauren L; McCarty, Kristofor; Neave, Nick
2016-01-01
The traditional assumption within the research literature on human sexually dimorphic traits has been that many sex differences have arisen from intersexual selection. More recently, however, there has been a shift toward the idea that many male features, including male lower-pitched voices and male beard growth, might have arisen predominantly through intrasexual selection: that is, to serve the purpose of male-male competition instead of mate attraction. In this study, using a unique set of video stimuli, we measured people's perceptions of the dominance and attractiveness of men who differ both in terms of voice pitch (4 levels from lower to higher pitched) and beard growth (4 levels from clean shaven to a month's hair growth). We found a nonlinear relationship between lower pitch and increased attractiveness; men's vocal attractiveness peaked at around 96 Hz. Beard growth had equivocal effects on attractiveness judgments. In contrast, perceptions of men's dominance simply increased with increasing masculinity (i.e., with lower-pitched voices and greater beard growth). Together, these results suggest that the optimal level of physical masculinity might differ depending on whether the outcome is social dominance or mate attraction. These dual selection pressures might maintain some of the documented variability in male physical and behavioral masculinity that we see today.
-
Alcohol consumption and high risk sexual behaviour among female ...
African Journals Online (AJOL)
Alcohol consumption has been associated with high risk sexual behaviour among key populations such as female sex workers. We explored the drivers of alcohol consumption and its relationship to high risk sexual behaviour. Participants were drawn from a cohort of 1 027 women selected from 'hot spots' in the suburbs of ...
-
Age at sexual initiation and factors associated with it among youths ...
African Journals Online (AJOL)
Bernt Lindtjorn
Objective: The objective of the study was to determine the median age at first sexual intercourse and the associated .... Wollo Zone, Amhara National Regional State, North East ..... censored. Urba n. Rura l. Residence rural/urban. Fig 2: Kaplan Meier curve showing log survival for ..... renting and selling pornography films.
-
Prevalence and correlates of sexual risk among male and female sex workers in Tijuana, Mexico.
Katsulis, Yasmina; Durfee, Alesha
2012-01-01
We investigated prevalence and correlates of sexual risk behaviours among male and female sex workers in Tijuana, Mexico, the busiest border crossing area on the US - Mexico border, analysing survey data from a purposive, cross-sectional sample of male and female sex workers who worked in a range of indoor and outdoor settings. Logistic regression was used to determine factors that were associated with sexual risk-taking, defined as failing to use a condom with last client. In bivariate regression models, gender, work setting (e.g., indoor vs. outdoor), poverty, engaging in survival sex, marital status and perceived drug addiction were correlated with sexual risk. When controlling for work location, housing insecurity, poverty, survival sex, marital status and perceived drug addiction, male sex workers were still 10 times more likely than female sex workers (FSW) to engage in sex without a condom during their last encounter with a client. And, although FSW were significantly more likely than males to have used a condom with a client, they were significantly less likely than males to have used a condom with their regular partner. Future research should further examine how gender shapes sexual risk activities in both commercial and non-commercial relationships.
-
The biology of human sexuality: evolution, ecology and physiology
Directory of Open Access Journals (Sweden)
PW Bateman
2006-09-01
Full Text Available Many evolutionary biologists argue that human sexual behaviour can be studied in exactly the same way as that of other species. Many sociologists argue that social influences effectively obscure, and are more important than, a reductionist biological approach to human sexual behaviour. Here,we authors attempt to provide a broad introduction to human sexual behaviour from a biological standpoint and to indicate where the ambiguous areas are. We outline the evolutionary selective pressures that are likely to have influenced human behaviour and mate choice in the past and in the present; ecological features that influence such things as degree of parental care and polygamy; and the associated physiology of human sexuality. Then they end with a discussion of �abnormal� sexuality.
-
Endocrinology of human female sexuality, mating, and reproductive behavior.
Motta-Mena, Natalie V; Puts, David A
2017-05-01
Hormones orchestrate and coordinate human female sexual development, sexuality, and reproduction in relation to three types of phenotypic changes: life history transitions such as puberty and childbirth, responses to contextual factors such as caloric intake and stress, and cyclical patterns such as the ovulatory cycle. Here, we review the endocrinology underlying women's reproductive phenotypes, including sexual orientation and gender identity, mate preferences, competition for mates, sex drive, and maternal behavior. We highlight distinctive aspects of women's sexuality such as the possession of sexual ornaments, relatively cryptic fertile windows, extended sexual behavior across the ovulatory cycle, and a period of midlife reproductive senescence-and we focus on how hormonal mechanisms were shaped by selection to produce adaptive outcomes. We conclude with suggestions for future research to elucidate how hormonal mechanisms subserve women's reproductive phenotypes. Copyright © 2016 Elsevier Inc. All rights reserved.
-
Parkes, Alison; Wight, Daniel; Hunt, Kate; Henderson, Marion; Sargent, James
2013-01-01
Sexual content in teenagers' media diets is known to predict early sexual behaviour. Research on sexual content has not allowed for the social context of media use, which may affect selection and processing of content. This study investigated whether sexual media content and/or contextual factors (co-viewing, parental media restrictions) were associated with early sexual behaviour using 2251 14–15 year-olds from Scotland, UK. A third (n = 733) reported sexual intercourse. In multivariable analysis the likelihood of intercourse was lower with parental restriction of sexual media and same-sex peer co-viewing; but higher with mixed-sex peer co-viewing. Parental co-viewing, other parental restrictions on media and sexual film content exposure were not associated with intercourse. Findings suggest the context of media use may influence early sexual behaviour. Specific parental restrictions on sexual media may offer more protection against early sex than other restrictions or parental co-viewing. Further research is required to establish causal mechanisms. PMID:24215959
-
Pelekanos, Michael; Stofman, Guy M; Niren, Neil
2016-12-13
The aim of this investigation was to determine, through two Investigational Review Board (IRB)-approved studies, if a new topical vasodilating cream (NTVC; Life Science Enhancement Corporation, Pittsburgh PA) could improve female sexual response. Study I subjectively evaluated sexual female response as accessed by a modification of the Female Intervention Efficacy Index (FIEI). FIEI was developed at the University of California as an immediate outcome measure of medical intervention to treat female sexual dysfunction.1 In Study II, 10 randomly selected positive responders from Study I were subsequently analyzed objectively with clitoral plethysmography in order to determine the effect of the NTVC and placebo on blood flow.2 RESULTS: In the subjective Study I (81 patients ranging in age from 18 to 63), a positive response trend for the NTVC was demonstrated compared to the placebo. In the objective Study II, 10 randomly selected patients who responded positive in Study I were objectively evaluated for response of increased blood flow in the clitoris after application of both the NTVC and placebo. The clitoral blood flow was shown to have increased with statistical significance for the NTVC in all 10 patients compared to the placebo, with the NTVC exhibiting an average 69% increase in clitoral blood flow. The female sexual response is complex. In the subjective Study I, the NTVC demonstrated positive trends for enhanced lubrication, genital sensation, intercourse, and overall sexual experience. In the objective Study II, 10 of the positive subjective responders from Study I were randomly selected to evaluate their response to the NTVC compared to the placebo. This was done via Doppler plethysmography (DP). All 10 patients demonstrated a statistically significant response rate for increase in clitoral blood flow using the NTVC compared to the placebo, with an average blood flow increase of 69%. This portion of the investigation demonstrates a significant positive end
-
Assessing sexual conflict in the Drosophila melanogaster laboratory model system
Rice, William R; Stewart, Andrew D; Morrow, Edward H; Linder, Jodell E; Orteiza, Nicole; Byrne, Phillip G
2006-01-01
We describe a graphical model of interlocus coevolution used to distinguish between the interlocus sexual conflict that leads to sexually antagonistic coevolution, and the intrinsic conflict over mating rate that is an integral part of traditional models of sexual selection. We next distinguish the ‘laboratory island’ approach from the study of both inbred lines and laboratory populations that are newly derived from nature, discuss why we consider it to be one of the most fitting forms of laboratory analysis to study interlocus sexual conflict, and then describe four experiments using this approach with Drosophila melanogaster. The first experiment evaluates the efficacy of the laboratory model system to study interlocus sexual conflict by comparing remating rates of females when they are, or are not, provided with a spatial refuge from persistent male courtship. The second experiment tests for a lag-load in males that is due to adaptations that have accumulated in females, which diminish male-induced harm while simultaneously interfering with a male's ability to compete in the context of sexual selection. The third and fourth experiments test for a lag-load in females owing to direct costs from their interactions with males, and for the capacity for indirect benefits to compensate for these direct costs. PMID:16612888
-
Possible evolutionary origins of human female sexual fluidity.
Kanazawa, Satoshi
2017-08-01
I propose an evolutionary theory of human female sexual fluidity and argue that women may have been evolutionarily designed to be sexually fluid in order to allow them to have sex with their cowives in polygynous marriage and thus reduce conflict and tension inherent in such marriage. In addition to providing an extensive definition and operationalization of the concept of sexual fluidity and specifying its ultimate function for women, the proposed theory can potentially solve several theoretical and empirical puzzles in evolutionary psychology and sex research. Analyses of the National Longitudinal Study of Adolescent Health (Add Health) confirm the theory's predictions that: (i) women (but not men) who experience increased levels of sexual fluidity have a larger number of children (suggesting that female sexual fluidity, if heritable, may be evolutionarily selected); (ii) women (but not men) who experience marriage or parenthood early in adult life subsequently experience increased levels of sexual fluidity; and (iii) sexual fluidity is significantly positively correlated with known markers of unrestricted sexual orientation among women whereas it is significantly negatively correlated with such markers among men. © 2016 Cambridge Philosophical Society.
-
Resource Elasticity of Offspring Survival and the Optimal Evolution of Sex Ratios
Wang, Rui-Wu; Wang, Ya-Qiang; He, Jun-Zhou; Li, Yao-Tang
2013-01-01
The fitness of any organisms includes the survival and reproductive rate of adults and the survival of their offspring. Environmental selection pressures might not affect these two aspects of an organism equally. Assuming that an organism first allocates its limited resources to maintain its survival under environmental selection pressure, our model, based on the evolutionarily stable strategy theory, surprisingly shows that the sex ratio is greatly affected by the environmental pressure intensity and by the reproductive resource elasticity of offspring survival. Moreover, the concept of the resource elasticity of offspring survival intrinsically integrates the ecological concepts of K selection and r selection. The model shows that in a species with reproductive strategy K, increased environmental selection pressure will reduce resource allocation to the male function. By contrast, in a species with reproductive strategy r, harsher environmental selection pressure will increase allocation to the male function. The elasticity of offspring survival might vary not only across species, but also across many other factors affecting the same species (e.g., age structure, spatial heterogeneity), which explains sex ratio differences across species or age structures and spatial heterogeneity in the same species. PMID:23468826
-
A comparison of rapists and sexual murderers on demographic and selected psychometric measures.
Oliver, Caroline J; Beech, Anthony R; Fisher, Dawn; Beckett, Richard
2007-06-01
This study compared 58 sexual murderers and 112 rapists who were about to undergo treatment in prison for their sexual offending behavior. The two groups were compared on background, personality, offense, and victim characteristics. The sexual murderer group were less likely to have been involved in a relationship at the time of their index offense, generally attacked older victims, and had higher self-esteem. The rapist sample were found to have more violent previous convictions and scored higher on measures of historical deviance (nonsexual), paranoid suspicion, and resentment. No differences were found on the personality or clinical syndrome scales of the Millon Clinical Multiaxial Inventory-III. However, the rapist sample had significantly higher mean scores on the Paranoid Suspicion, Resentment, and Self-Esteem subscales of the Antisocial Personality Questionnaire. Future research should compare the two groups on dynamic or changeable factors to determine differential treatment needs.
-
[Sex differences in sexual versus emotional jealousy: evolutionary approach and recent discussions].
Demirtaş Madran, H Andaç
2008-01-01
Sex differences in jealousy have been reported widely in the social psychological, clinical psychological, psychiatric, and anthropological literature. Many of the studies conducted on jealousy have focused on the sex differences in the level of reported jealousy. Most research has reported that there is no difference between men and women regarding the level of reported jealousy, but there are some sex differences between sexual and emotional jealousy. Evolutionary psychologists divide jealousy into 2 dimensions based on their observations and empirical research findings: Sexual jealousy and emotional jealousy. Sexual jealousy is knowing or suspecting that one's partners has had sexual relationship with a third person, whereas emotional jealousy is triggered by partner's emotional involvement with and/or love for another person. The parental investment model, which extended Darwin's explanations of sexual selection, provides a useful theoretical framework for studying sexual and emotional jealousy. According to this model sexual selection is driven by differential parental investment by men and women; men should experience more sexual jealousy than women and women should experience more emotional jealousy than men. Considerable research has focused on testing this hypothesis and, with a few exceptions, the results are generally consistent with the evolutionary account. In this study, firstly, a brief definition of the sexual and emotional jealousy will be given. Then, sex differences in sexual and emotional jealousy will be explained according to the evolutionary theory. Finally, the results of empirical studies and critiques of the evolutionary model will be given.
-
Personal Choices, Personal Power. Career Survival Kit for Teen Education and Employment.
Lindner, A. Frances
This workbook is one component of the Career Survival Kit prepared for teenage parents in Wisconsin. The workbook is designed to help teen parents identify their choices in preventing another pregnancy. It presents some thoughts about sexual decisions and responsibility. Birth control methods are described to help teens decide the best method for…
-
Sexual Dating Aggression Across Grades 8 Through 12: Timing and Predictors of Onset
Reyes, H. Luz McNaughton; Foshee, Vangie A.
2013-01-01
Investigators have identified a number of factors that increase risk for physical and psychological dating abuse perpetration during adolescence, but as yet little is known about the etiology of sexual dating aggression during this critical developmental period. This is an important gap in the literature given that research suggests that patterns of sexual dating violence that are established during this period may carry over into young adulthood. Using a sample of 459 male adolescents (76% White, 19% Black), the current study used survival analysis to examine the timing and predictors of sexual dating aggression perpetration onset across grades 8 through 12. Risk for sexual dating aggression onset increased across early adolescence, peaked in the 10th grade, and desisted thereafter. As predicted based on the Confluence Model of sexual aggression, associations between early physical aggression towards peers and dates and sexual aggression onset were stronger for teens reporting higher levels of rape myth acceptance. Contrary to predictions, inter-parental violence, prior victimization experiences, and parental monitoring knowledge did not predict sexual dating aggression onset. Findings support the notion that risk factors may work synergistically to predict sexual dating aggression and highlight the importance of rape myth acceptance as a construct that should be addressed by violence prevention programs. PMID:23180071
-
Patterns of Asexuality in China: Sexual Activity, Sexual and Romantic Attraction, and Sexual Desire.
Zheng, Lijun; Su, Yanchen
2018-05-01
This study examined patterns of asexuality in Chinese asexual people in terms of sexual activities, sexual/romantic attraction, and sexual desire. The sample included 227 (64 men and 163 women) asexual participants and 57 (26 men and 31 women) uncertain asexual participants recruited from social networks for asexual people. The control group included 217 (115 men and 102 women) heterosexual participants recruited from general social networks. Participants scoring 40 or higher on the Asexuality Identification Scale were classified as asexual. Asexual participants reported having less frequent masturbation, sexual intercourse experience, and sexual and romantic attraction compared to heterosexual participants. Lower sexual attraction among asexuals indicated that "people who experience little or no sexual attraction" would be a more appropriate definition of asexuality. The pattern of uncertain asexual participants' sexual/romantic attraction and sexual desire was intermediate between heterosexual and asexual participants. Asexual participants scored significantly lower on dyadic sexual desire and slightly lower on solitary sexual desire than heterosexual participants. There were significant differences in sexual activities and solitary sexual desire among romantic orientation categories. Homoromantic participants showed higher dyadic sexual desire and were more likely to engage in masturbation, indicating the heterogeneity among asexual people. The findings indicated that Chinese asexual people showed similar patterns of asexuality as in Western nations. Specifically, asexual people have little or no sexual attraction, non-partner-orientated sexual desire, and are heterogeneous in sexual activities and sexual desire. This implies similar mechanisms underlying the etiology of asexuality across cultures.
-
Howard, J R; O'Neill, S; Travers, C
2006-10-01
To investigate the sexual behavior, sexual relationships, sexual satisfaction, sexual dysfunction and sexual distress in a population of older urban Australian women. In 2004, 474 women participating in the Longitudinal Assessment of Ageing in Women (LAW) Study completed a series of questionnaires about sexuality. They included the Short Personal Experiences Questionnaire (SPEQ), Relationship Assessment Scale (RAS), Female Sexual Distress Scale (FSDS), questions concerning past sexual abuse based on the Sex in Australia Study, and questions comparing present and past sexual interest and activity. The percentage of women with partners ranged from 83.3% in the 40 - 49-year age group to 46.4% women in the 70 - 79-year age group. The sexual ability of partners diminished markedly with age, with only 4.8% of the partners using medication to enable erections. Only 2.5% of women reported low relationship satisfaction. The incidence of sexual distress was also low, being reported by only 5.7% of women. Younger women and women with partners had higher levels of distress than older women. Indifference to sexual frequency rose from 26.7% in women aged 40 - 49 years to 72.3% in the 70 - 79-year age group. Past sexual abuse was recalled by 22.7% of women and 11.6% recalled multiple episodes of abuse. Women who recalled abuse had lower scores for satisfaction with sexual frequency. It appears from this study that there is a wide range of sexual experience amongst aging women, from never having had a sexual partner, to having solitary sex, to having a relationship with or without sex into the seventh decade. As women age, they experience a decrease in sexual activity, interest in sex, and distress about sex. This may be associated with the loss of intimate relationships as part of separation, divorce or bereavement. Decreased sexual activity with aging may be interpreted as a biological phenomenon (part of the aging process) or as sexual dysfunction, or it may be the result of
-
Dańko, Aleksandra; Schaible, Ralf; Pijanowska, Joanna; Dańko, Maciej J
2018-01-01
Budding hydromedusae have high reproductive rates due to asexual reproduction and can occur in high population densities along the coasts, specifically in tidal pools. In laboratory experiments, we investigated the effects of population density on the survival and reproductive strategies of a single clone of Eleutheria dichotoma . We found that sexual reproduction occurs with the highest rate at medium population densities. Increased sexual reproduction was associated with lower budding (asexual reproduction) and survival probability. Sexual reproduction results in the production of motile larvae that can, in contrast to medusae, seek to escape unfavorable conditions by actively looking for better environments. The successful settlement of a larva results in starting the polyp stage, which is probably more resistant to environmental conditions. This is the first study that has examined the life-history strategies of the budding hydromedusa E. dichotoma by conducting a long-term experiment with a relatively large sample size that allowed for the examination of age-specific mortality and reproductive rates. We found that most sexual and asexual reproduction occurred at the beginning of life following a very rapid process of maturation. The parametric models fitted to the mortality data showed that population density was associated with an increase in the rate of aging, an increase in the level of late-life mortality plateau, and a decrease in the hidden heterogeneity in individual mortality rates. The effects of population density on life-history traits are discussed in the context of resource allocation and the r/K-strategies' continuum concept.
-
Sexual reproduction and the evolution of microbial pathogens.
Heitman, Joseph
2006-09-05
Three common systemic human fungal pathogens--Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus--have retained all the machinery to engage in sexual reproduction, and yet their populations are often clonal with limited evidence for recombination. Striking parallels have emerged with four protozoan parasites that infect humans: Toxoplasma gondii, Trypanosoma brucei, Trypanosoma cruzi and Plasmodium falciparum. Limiting sexual reproduction appears to be a common virulence strategy, enabling generation of clonal populations well adapted to host and environmental niches, yet retaining the ability to engage in sexual or parasexual reproduction and respond to selective pressure. Continued investigation of the sexual nature of microbial pathogens should facilitate both laboratory investigation and an understanding of the complex interplay between pathogens, hosts, vectors, and their environments.
-
Sexuality education in Malaysia: perceived issues and barriers by professionals.
Khalaf, Zahra Fazli; Low, Wah Yun; Merghati-Khoei, Effat; Ghorbani, Behzad
2014-07-01
This research explored the perspectives of Malaysian professionals on the issues and barriers affecting the implementation of sexuality education in Malaysia. This qualitative study involved in-depth interviews with 15 key professionals working in the field of sexuality and reproductive health in Malaysia. Thematic analysis was selected to analyze data. Barriers to sexuality education were perceived from 5 aspects: feasibility, acceptability, accountability, strategies, and community unawareness. Respondents believed that implementing national sexuality education is a time-consuming project. They regarded Malaysian multicultural society as a barrier to national sexuality education, and they believed that school-based sexuality education is not easily accomplished in Malaysia; also abstinence-only policy restricts the access of young people to accurate information. Lack of community involvement was perceived as a key concern to sexuality education. Campaigning to promote awareness of families, teachers, community leaders, and policy makers are recommended to help establishing national sexuality education in Malaysia. © 2014 APJPH.
-
Directory of Open Access Journals (Sweden)
Gert Martin Hald, PhD
2018-03-01
Hald GM, Stulhofer A, Lange T, et al. Sexual Arousal and Sexually Explicit Media (SEM: Comparing Patterns of Sexual Arousal to SEM and Sexual Self-Evaluations and Satisfaction Across Gender and Sexual Orientation. Sex Med 2018;6:30–38.
-
Survival analysis of dialysis patients in selected hospitals of lahore city
International Nuclear Information System (INIS)
Ahmad, Z.; Shahzad, I.
2015-01-01
There are several reasons which are directly or indirectly relate to affect the survival time of End Stage Renal Disease (ESRD) patients. This study was done to analyse the survival rate of ESRD patients in Lahore city, and to evaluate the influence of various risk factors and prognostic factors on survival of these patients. Methods: A sample of 40 patients was taken from the Jinnah Hospital Lahore and Lahore General Hospital by using the convenience sampling technique. The Log Rank Test was used to determine the significant difference between the categories of qualitative variables of ESRD patients. Multivariate Cox Regression Analysis was used to analyse the effect of different clinical and socio-economic variables on the survival time of these patients. Results: Different qualitative variables like: age, marital status, BMI, comorbid factors, diabetes type, gender, income level, place, risk factor like diabetes, ischemic heart disease, hypertension and Hepatitis status were analysed on the basis of Log Rank Test. While age and comorbid factors were found to be statistically significant which showed that the distribution of age and comorbid factors were different. By using the Cox Regression analysis the coefficient of Mass, serum albumin and family history of diabetes were found to be significant. Conclusions: There were some of the factors which had been taken for the analysis came out less or more significant in patients of ESRD. So it was concluded that mostly clinical factors which were Mass of the Patient, Serum Albumin and Family History of Diabetes made significant contribution towards the survival status of patients. (author)
-
Dysregulated sexuality and high sexual desire: distinct constructs?
Winters, Jason; Christoff, Kalina; Gorzalka, Boris B
2010-10-01
The literature on dysregulated sexuality, whether theoretical, clinical or empirical, has failed to differentiate the construct from high sexual desire. In this study, we tested three hypotheses which addressed this issue. A sample of 6458 men and 7938 women, some of whom had sought treatment for sexual compulsivity, addiction or impulsivity, completed an online survey comprised of various sexuality measures. Men and women who reported having sought treatment scored significantly higher on measures of dysregulated sexuality and sexual desire. For men, women, and those who had sought treatment, dysregulated sexuality was associated with increased sexual desire. Confirmatory factor analysis supported a one-factor model, indicating that, in both male and female participants, dysregulated sexuality and sexual desire variables loaded onto a single underlying factor. The results of this study suggest that dysregulated sexuality, as currently conceptualized, labelled, and measured, may simply be a marker of high sexual desire and the distress associated with managing a high degree of sexual thoughts, feelings, and needs.
-
Sexuality in older adults: Clinical and psychosocial dilemmas
Directory of Open Access Journals (Sweden)
Isha Dhingra
2016-01-01
Full Text Available The present review aims to throw some light on the various aspects of sexuality in older adults and the challenges faced by medical professionals working in this area. Keyword searches using the terms "sexuality," "sexual dysfunction," "geriatric," "old age," and others in combination were carried out on PubMed, Google Scholar, and the Cochrane Database of Systematic Reviews. Relevant clinical trials, case studies, and review papers were selected. This was further supplemented with the clinical experience of the authors, who work with older patients in a psychiatric outpatient setting with a dedicated sexual disorders clinic. Sexuality is a lifelong phenomenon and its expression a basic human right across all ages. However, the construct of normalcy for sex in aging is blurred, with agism playing a distinct role. Older adults face much stigma when expressing sexual desires or concerns, both from their own families and the health-care system. Sexual dysfunctions due to comorbid medical illnesses and medications are often treatable. Evidence-based treatments for sexual dysfunction in the elderly, lesbian, gay, bisexual, transgender, and queer, and other orientations are especially underrepresented in research; available research has several limitations. Sexuality in people with dementia and sexual rights in nursing homes are gray areas. Medical training, treatment guidelines, and health-care facilities all need to be stepped up in terms of awareness and quality of care provided to the elderly with concerns related to sexuality.
-
Sexual harassment of the physiotherapist in South Africa
Directory of Open Access Journals (Sweden)
L. Bütow-Dûtoit
2006-01-01
Full Text Available No study has been conducted on sexual harassment of physiotherapists in South Africa and it is therefore not known whether harassment occurs and if it does, to what extent. To this purpose, a questionnaire on sexual harassment and other sexual-related issues in the physiotherapy work environment in South Africa, was sent to a random selection of 982 physiotherapists registered with the Health Professions Council of South Africa. The response rate was 32%. This paper presents the results of the first half of the questionnaire, which was devoted to sexual harassment of the physiotherapist. Approximately 60% had experienced sexual harassment, of which 83.98% had been perpetrated by patients. Only 5.82% of the respondents had received some form of information in this regard. The most common form of harassment was requests for a hug or kiss.
-
Feeding ecology and sexual dimorphism in a speciose flower beetle clade (Hopliini: Scarabaeidae
Directory of Open Access Journals (Sweden)
Jonathan F. Colville
2018-06-01
Full Text Available The relationship between feeding ecology and sexual dimorphism is examined in a speciose South African monkey beetle clade. We test whether feeding and mating at a fixed site (embedding guild is associated with greater levels of sexual dimorphism and possibly sexual selection than species using unpredictable feeding resources (non-embedding guild. Sexual dimorphism was measured using a point scoring system for hind leg and colour across the two feeding guilds for >50% of the regional fauna. Quantification of hind leg dimorphism using a scoring system and allometric scaling were used to identify traits subject to sexual selection. Feeding guild had a significant effect on hind leg dimorphism, with embedders having high and non-embedders low scores. The sessile and defendable distribution of females on stable platform flowers may favour contests and associated hind leg weaponry. In contrast, degree of colour dimorphism between the sexes was not associated with any particular feeding guild, and may serve to reduce male conflict and combat. Embedder males had high proportions (∼76% of species with positive allometric slopes for almost all hind leg traits. For male non-embedders, only ∼37% of species showed positive scaling relationships. Phylogenetic data, in conjunction with behavioural data on the function of leg weaponry and visual signalling among males is needed to better understand the link between sexual dimorphism and sexual selection in the radiation of the monkey beetles.
-
Amos, Natalie; McCabe, Marita
2017-10-01
Limited research exists on the implications of feeling sexually attractive for various aspects of sexuality and sexual relationships. This article examined associations between self-perceived sexual attractiveness and sexual esteem, sexual satisfaction and amount of sexual experience, among both men and women who identified as heterosexual (n = 1017), gay or lesbian (n = 1225) or bisexual (n = 651). Results of the study demonstrated that positive self-perceptions of sexual attractiveness predicted greater sexual esteem, greater sexual satisfaction, a higher frequency of sexual activity with others and a larger number of sexual partners among both men and women who identified as heterosexual, gay, lesbian or bisexual. The findings suggest that feeling sexually attractive may have implications for how an individual experiences their sexuality and sexual relationships regardless of their gender or sexual orientation. The importance of considering an individual's self-perceptions of sexual attractiveness when they present with concerns related to their sexual experiences or relationships, and the potential benefits of educational and therapeutic interventions designed to enhance self-perceptions of sexual attractiveness are discussed. © 2015 International Union of Psychological Science.
-
Adaptive Memory: Is Survival Processing Special?
Nairne, James S.; Pandeirada, Josefa N. S.
2008-01-01
Do the operating characteristics of memory continue to bear the imprints of ancestral selection pressures? Previous work in our laboratory has shown that human memory may be specially tuned to retain information processed in terms of its survival relevance. A few seconds of survival processing in an incidental learning context can produce recall…
-
Sexuality and Sexual Rights in Muslim Societies
Liz Ercevik Amado
2009-01-01
In August 2008, the Coalition for Sexual and Bodily Rights in Muslim Societies (CSBR) organized the CSBR Sexuality Institute, the first international Institute on sexuality and sexual rights in Muslim societies in Malaysia. Liz Amado presents how the Institute expanded the discourse, knowledge and thinking around sexuality in Muslim societies, as well as providing a unique space for the much needed exchange of information and experience among sexual rights advocates. Development (2009) 52, 59...
-
Exploring infertile women's experiences about sexual life: A qualitative study.
Kohan, Shahnaz; Ghasemi, Zahra; Beigi, Marjan
2015-01-01
Infertility is a serious problem in a couple's life that affects their marriage relationships. So, dissatisfaction with sexual function resulting from interpersonal problems is common among these couples. This qualitative study aimed to explore the experiences of infertile women in their sexual life. This is a qualitative study with a phenomenological approach. The participants were 20 infertile women referring to the health care centers and infertility clinics of Isfahan and were selected through purposive sampling. Data were collected by tape recording of deep interviews and analyzed by Colaizzi's method. Analysis of the participants' experiences led to five main concepts: "Disturbed in femininity-body image," "discouragement of sexual relations," "sacrifice of sexual pleasure for the sake of getting pregnant," "confusion in sexual relation during infertility treatment," and "striving to protect their marriage." Findings revealed that infertility affects women's different aspects of sexual life, especially disturbance in femininity-body image and sexual reluctance. With regard to women's willingness to protect their matrimonial life and prevent sexual trauma as a destroying factor for their family's mental health, it seems sexual counseling is necessary for infertile couples.
-
Sexual Well-Being in Older Women: The Relevance of Sexual Excitation and Sexual Inhibition.
Bell, Suzanne; Reissing, Elke D
2017-01-01
The aim of this study was to use the dual control model of sexual response (DCM) to investigate variation in sexual well-being among women 50 years of age and older. Data from 185 women 50 years of age and older (M = 59.46, SD = 6.96) were used to examine the relationships between sexual excitation (SE) and sexual inhibition (SI) and their lower-order factors to indicators of sexual well-being (i.e., sexual functioning, satisfaction, distress, frequency of sexual activity, and breadth of sexual behavior). Possible moderating factors were also explored. Independently, SE and SI were associated with the majority of the indicators of sexual well-being, and the directions of associations were consistent with the tenets of the DCM. SE and SI lower-order factors were significant predictors of sexual function, satisfaction, and frequency of sexual activity. Sexual distress was predicted more strongly by SI factors and breadth of sexual behavior by one SE lower-order factor (arousability). Partner physical and mental health and participant's own mental health were identified as moderating variables of these associations. Findings of this study are discussed considering the contribution of the DCM to understanding the role of diversity in older women's sexual well-being.
-
Rare genetic variation in UNC13A may modify survival in amyotrophic lateral sclerosis
Gaastra, Benjamin; Shatunov, Aleksey; Pulit, Sara; Jones, Ashley R; Sproviero, William; Gillett, Alexandra; Chen, Zhongbo; Kirby, Janine; Fogh, Isabella; Powell, John F; Leigh, P Nigel; Morrison, Karen E; Shaw, Pamela J; Shaw, Christopher E; van den Berg, Leonard H; Veldink, Jan H; Lewis, Cathryn M; Al-Chalabi, Ammar
2016-01-01
Our objective was to identify whether rare genetic variation in amyotrophic lateral sclerosis (ALS) candidate survival genes modifies ALS survival. Candidate genes were selected based on evidence for modifying ALS survival. Each tail of the extreme 1.5% of survival was selected from the UK MND DNA
-
Directory of Open Access Journals (Sweden)
Olivia Nankinga
2016-05-01
Full Text Available Abstract Background Sexually transmitted infections (STIs are a major reproductive and public health concern, especially in the era of HIV/AIDS. This study examined the relationship between sexual empowerment and STI status of women in union (married or cohabiting in Uganda, controlling for sexual behaviour, partner factors, and women’s background characteristics. Methods The study, based on data from the 2011 Uganda Demographic and Health Survey (UDHS, analysed 1307 weighted cases of women age 15–49 in union and selected for the domestic violence module. Chi-squared tests and multivariate logistic regressions were used to examine the predicators of STI status. The main explanatory variables included sexual empowerment, involvement in decision making on own health, experience of any sexual violence, condom use during last sex with most recent partner, number of lifetime partners and partner control behaviours. Sexual empowerment was measured with three indicators: a woman’s reported ability to refuse sex, ability to ask her partner to use a condom, and opinion regarding whether a woman is justified to refuse sex with her husband if he is unfaithful. Results Results show that 28 % of women in union reported STIs in the last 12 months. Sexual violence and number of lifetime partners were the strongest predictors of reporting STIs. Women’s sexual empowerment was a significant predictor of their STI status, but, surprisingly, the odds of reporting STIs were greater among women who were sexually empowered. Reporting of STIs was negatively associated with a woman’s participation in decision-making with respect to her own health, and was positively associated with experience of sexual violence, partner’s controlling behaviour, and having more than one life partner. Conclusions Our findings suggest that, with respect to STIs, sexual empowerment as measured in the study does not protect women who have sexually violent and controlling
-
Directory of Open Access Journals (Sweden)
Luciana Takada
Full Text Available Reproductive traits are of the utmost importance for any livestock farming, but are difficult to measure and to interpret since they are influenced by various factors. The objective of this study was to detect associations between known polymorphisms in candidate genes related to sexual precocity in Nellore heifers, which could be used in breeding programs. Records of 1,689 precocious and non-precocious heifers from farms participating in the Conexão Delta G breeding program were analyzed. A subset of single nucleotide polymorphisms (SNP located in the region of the candidate genes at a distance of up to 5 kb from the boundaries of each gene, were selected from the panel of 777,000 SNPs of the High-Density Bovine SNP BeadChip. Linear mixed models were used for statistical analysis of early heifer pregnancy, relating the trait with isolated SNPs or with haplotype groups. The model included the contemporary group (year and month of birth as fixed effect and parent of the animal (sire effect as random effect. The fastPHASE® and GenomeStudio® were used for reconstruction of the haplotypes and for analysis of linkage disequilibrium based on r2 statistics. A total of 125 candidate genes and 2,024 SNPs forming haplotypes were analyzed. Statistical analysis after Bonferroni correction showed that nine haplotypes exerted a significant effect (p<0.05 on sexual precocity. Four of these haplotypes were located in the Pregnancy-associated plasma protein-A2 gene (PAPP-A2, two in the Estrogen-related receptor gamma gene (ESRRG, and one each in the Pregnancy-associated plasma protein-A gene (PAPP-A, Kell blood group complex subunit-related family (XKR4 and mannose-binding lectin genes (MBL-1 genes. Although the present results indicate that the PAPP-A2, PAPP-A, XKR4, MBL-1 and ESRRG genes influence sexual precocity in Nellore heifers, further studies are needed to evaluate their possible use in breeding programs.
-
Sexual dysfunction among youth: an overlooked sexual health concern.
Moreau, Caroline; Kågesten, Anna E; Blum, Robert Wm
2016-11-18
There is growing recognition that youth sexual health entails a broad range of physical, emotional and psychosocial responses to sexual interactions, yet little is known about sexual dysfunctions and well being in youth populations. This study explored sexual dysfunctions among youth and its associations with other domains of sexual health. Sexual dysfunctions were defined as: problems related to orgasm, pain during intercourse, lack of sexual desire or sexual pleasure. Data were drawn from the 2010 French national sexual and reproductive health survey comprising a random sample of 2309 respondents aged 15-24 years. The current analysis included 842 females and 642 males who had sexual intercourse in the last 12 months. Chi square tests were used to test for differences in sexual dysfunctions by sex and explore associations with other domains of sexual health. Half of females (48%) reported at least one sexual dysfunction versus 23% of males. However, over half (57%) of youth reporting at least one dysfunction did not consider this to hinder their sexuality. Altogether, 31% of females cited at least one sexual dysfunction hindering their sexuality-more than three times the 9% of males. Sexual dysfunction was strongly and inversely related to sexual satisfaction for both males and females and additionally to a recent diagnosis of STI or unintended pregnancy for females. Sexual dysfunctions hindering sexuality were also correlated with a history of unintended pregnancy among males. While most youth in France enjoy a satisfying sexual life, sexual dysfunction is common, especially among females. Public health programs and clinicians should screen for and address sexual dysfunction, which substantially reduce youth sexual wellbeing.
-
Clark, Rulon W; Schuett, Gordon W; Repp, Roger A; Amarello, Melissa; Smith, Charles F; Herrmann, Hans-Werner
2014-01-01
Long-term studies of individual animals in nature contribute disproportionately to our understanding of the principles of ecology and evolution. Such field studies can benefit greatly from integrating the methods of molecular genetics with traditional approaches. Even though molecular genetic tools are particularly valuable for species that are difficult to observe directly, they have not been widely adopted. Here, we used molecular genetic techniques in a 10-year radio-telemetric investigation of the western diamond-backed rattlesnake (Crotalus atrox) for an analysis of its mating system and to measure sexual selection. Specifically, we used microsatellite markers to genotype 299 individuals, including neonates from litters of focal females to ascertain parentage using full-pedigree likelihood methods. We detected high levels of multiple paternity within litters, yet found little concordance between paternity and observations of courtship and mating behavior. Larger males did not father significantly more offspring, but we found evidence for size-specific male-mating strategies, with larger males guarding females for longer periods in the mating seasons. Moreover, the spatial proximity of males to mothers was significantly associated with reproductive success. Overall, our field observations alone would have been insufficient to quantitatively measure the mating system of this population of C. atrox, and we thus urge more widespread adoption of molecular tools by field researchers studying the mating systems and sexual selection of snakes and other secretive taxa.
-
Walker, Dave P; Messman-Moore, Terri L; Ward, Rose Marie
2011-01-01
In previous studies, number of sexual partners and sexual assertiveness were examined as independent risk factors for sexual victimization among college women. Using a sample of 335 college women, this study examined the interaction of number of sexual partners and sexual assertiveness on verbal sexual coercion and rape. Approximately 32% of the sample reported unwanted sexual intercourse, 6.9% (n = 23) experienced verbal sexual coercion, 17.9% (n = 60) experienced rape, and 7.2% (n = 24) experienced both. As number of sexual partners increased, instances of verbal sexual coercion increased for women low in relational sexual assertiveness but not for women high in relational sexual assertiveness. A similar relationship was not found for rape. Among women who experienced both verbal sexual coercion and rape, increases in number of partners in the context of low refusal and relational assertiveness were associated with increases in verbal sexual coercion and rape. Findings suggest sexual assertiveness is related to fewer experiences of sexual coercion.
-
A prime determinant in selecting dialysis modality: peritoneal dialysis patient survival
Directory of Open Access Journals (Sweden)
Hyunwook Kim
2017-03-01
Full Text Available The number of patients with end-stage renal disease (ESRD has rapidly increased, as has the cost of dialysis. Peritoneal dialysis (PD is an established treatment for ESRD patients worldwide; it has a variety of advantages, including autonomy and flexibility, as well as economic benefits in many countries compared to hemodialysis (HD. However, the long-term survival rate of PD remains poor. Although direct comparison of survival rate between the dialysis modalities by randomized controlled trials is difficult due to the ethical issues, it has always been a crucial point when deciding which dialysis modality should be recommended to patients. Recently, in many countries, including the United States, Brazil, Spain, Australia, and New Zealand, the survival rate in PD patients has significantly improved. PD patient survival in Korea has also improved, but Korean PD patients are known to have higher risk of mortality and major adverse cardiovascular, cerebrovascular events than HD patients. Herein, we further evaluate why Korean PD patients had worse outcomes; we suggest that special attention should be paid to patients with diabetes, coronary artery disease, or congestive heart failure when they choose PD as the first dialysis modality in order to reduce mortality risk.
-
van Anders, Sari M
2015-07-01
Sexual orientation typically describes people's sexual attractions or desires based on their sex relative to that of a target. Despite its utility, it has been critiqued in part because it fails to account for non-biological gender-related factors, partnered sexualities unrelated to gender or sex, or potential divergences between love and lust. In this article, I propose Sexual Configurations Theory (SCT) as a testable, empirically grounded framework for understanding diverse partnered sexualities, separate from solitary sexualities. I focus on and provide models of two parameters of partnered sexuality--gender/sex and partner number. SCT also delineates individual gender/sex. I discuss a sexual diversity lens as a way to study the particularities and generalities of diverse sexualities without privileging either. I also discuss how sexual identities, orientations, and statuses that are typically seen as misaligned or aligned are more meaningfully conceptualized as branched or co-incident. I map out some existing identities using SCT and detail its applied implications for health and counseling work. I highlight its importance for sexuality in terms of measurement and social neuroendocrinology, and the ways it may be useful for self-knowledge and feminist and queer empowerment and alliance building. I also make a case that SCT changes existing understandings and conceptualizations of sexuality in constructive and generative ways informed by both biology and culture, and that it is a potential starting point for sexual diversity studies and research.
-
Lou, Jiunn-Horng; Chen, Sheng-Hwang; Li, Ren-Hau; Yu, Hsing-Yi
2011-06-01
The purpose of this study was to test a model of sexual self-concept and sexual risk cognition affecting sexual communication in Taiwanese adolescents. Parent-adolescent sexual communication has been shown to influence adolescent sexual behaviour. Self-concept is an important predictor of human behaviour, especially sexual behaviour. Few researchers have assessed sexual self-concept in adolescents, despite its clear relevance to understanding adolescent sexual behaviour. A cross-sectional survey with convenience sampling was used in this study. In 2009, data were collected by questionnaire from 748 adolescent students at a junior college in Taiwan. The results revealed that the postulated model fits the data from this study well. Sexual self-concept significantly predicts sexual risk cognition and sexual communication. Sexual risk cognition significantly predicts sexual communication and has an intervening effect on the relationship between sexual self-concept and sexual communication. Sexual risk cognition is important in explaining sexuality in adolescents. Sexual self-concept has both direct and indirect effects on sexual communication. Our findings provide concrete directions for school educators in developing sexual health programmes to increase adolescent sexual self-concept and sexual communication with their parents. Future sexual health programmes about sexual self-concept and sexual risk cognition must add for increasing adolescent's sexual communication with their parents. © 2010 Blackwell Publishing Ltd.
-
Does Sexual Selection Influence Ornamentation of Hemipenes in Old World Snakes?
Andonov, Kostadin; Natchev, Nikolay; Kornilev, Yurii V; Tzankov, Nikolay
2017-09-01
In the present study, we investigated and documented the morphology of the male copulatory organs (hemipenes) in fifteen wide-ranging snake species. The species represent four families (Boidae, Colubridae, Lamprophiidae, and Viperidae) and ten genera. We applied the same preparation techniques for all species, successfully everting and expanding the organs completely. The detailed description of the general morphology of the male copulatory organs was based on 31 specimens. Our data were compared with published observations and we point out some incorrectly described details in previous investigations. We provide the first description of the hemipenial morphology for three ophidian species (Elaphe sauromates, Telescopus fallax, and Malpolon insignitus). In addition to the morphological characteristics of the hemipenes presented in the research, we propose the adoption of a standardized index describing the hemipenial proportions. The immense variation in hemipenial morphology presupposes its dynamic evolution, but we suggest that many of the significant structures observed here may have escaped previous researchers due to differing methodologies. Some of the highly ornamented morphologies that we describe are consistent with a locking mechanism during copulation. However, other morphologies may relate to the variety of mating behaviors observed. As a result, we propose that sexual selection is the major driver affecting the hemipenial ornamentation in snakes. Anat Rec, 300:1680-1694, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
-
Human sexual conflict from molecules to culture.
Gorelik, Gregory; Shackelford, Todd K
2011-12-15
Coevolutionary arms races between males and females have equipped both sexes with mutually manipulative and defensive adaptations. These adaptations function to benefit individual reproductive interests at the cost of the reproductive interests of opposite-sex mates, and arise from evolutionary dynamics such as parental investment (unequal reproductive costs between the sexes) and sexual selection (unequal access to opposite-sex mates). Individuals use these adaptations to hijack others' reproductive systems, psychological states, and behaviors--essentially using other individuals as extended phenotypes of themselves. Such extended phenotypic manipulation of sexual rivals and opposite-sex mates is enacted by humans with the aid of hormones, pheromones, neurotransmitters, emotions, language, mind-altering substances, social institutions, technologies, and ideologies. Furthermore, sexual conflict may be experienced at an individual level when maternal genes and paternal genes are in conflict within an organism. Sexual conflict may be physically and emotionally destructive, but may also be exciting and constructive for relationships. By extending the biological concept of sexual conflict into social and cultural domains, scholars may successfully bridge many of the interdisciplinary gaps that separate the sciences from the humanities.
-
Everett, Bethany G
2013-02-01
The terms MSM (men who have sex with men) and WSW (women who have sex with women) have been used with increasing frequency in the public health literature to examine sexual orientation disparities in sexual health. These categories, however, do not allow researchers to examine potential differences in sexually transmitted infection (STI) risk by sexual orientation identity. Using data from the National Longitudinal Survey of Adolescent Health, this study investigated the relationship between self-reported STIs and both sexual orientation identity and sexual behaviors. Additionally, this study examined the mediating role of victimization and STI risk behaviors on the relationship between sexual orientation and self-reported STIs. STI risk was found to be elevated among heterosexual-WSW and bisexual women, whether they reported same-sex partners or not, whereas gay-identified WSW were less likely to report an STI compared to heterosexual women with opposite sex relationships only. Among males, heterosexual-identified MSM did not have a greater likelihood of reporting an STI diagnosis; rather, STI risk was concentrated among gay and bisexual identified men who reported both male and female sexual partners. STI risk behaviors mediated the STI disparities among both males and females, and victimization partially mediated STI disparities among female participants. These results suggest that relying solely on behavior-based categories, such as MSM and WSW, may mischaracterize STI disparities by sexual orientation.
-
Sexual dysfunction among youth: an overlooked sexual health concern
Directory of Open Access Journals (Sweden)
Caroline Moreau
2016-11-01
Full Text Available Abstract Background There is growing recognition that youth sexual health entails a broad range of physical, emotional and psychosocial responses to sexual interactions, yet little is known about sexual dysfunctions and well being in youth populations. This study explored sexual dysfunctions among youth and its associations with other domains of sexual health. Sexual dysfunctions were defined as: problems related to orgasm, pain during intercourse, lack of sexual desire or sexual pleasure. Methods Data were drawn from the 2010 French national sexual and reproductive health survey comprising a random sample of 2309 respondents aged 15-24 years. The current analysis included 842 females and 642 males who had sexual intercourse in the last 12 months. Chi square tests were used to test for differences in sexual dysfunctions by sex and explore associations with other domains of sexual health. Results Half of females (48% reported at least one sexual dysfunction versus 23% of males. However, over half (57% of youth reporting at least one dysfunction did not consider this to hinder their sexuality. Altogether, 31% of females cited at least one sexual dysfunction hindering their sexuality—more than three times the 9% of males. Sexual dysfunction was strongly and inversely related to sexual satisfaction for both males and females and additionally to a recent diagnosis of STI or unintended pregnancy for females. Sexual dysfunctions hindering sexuality were also correlated with a history of unintended pregnancy among males. Conclusion While most youth in France enjoy a satisfying sexual life, sexual dysfunction is common, especially among females. Public health programs and clinicians should screen for and address sexual dysfunction, which substantially reduce youth sexual wellbeing.
-
GENDER DIFFERENCES IN PERCEPTIONS OF SEXUAL INTENT: A QUALITATIVE REVIEW AND INTEGRATION
Lindgren, Kristen P.; Parkhill, Michele R.; George, William H.; Hendershot, Christian S.
2009-01-01
Men appear to interpret people’s behaviors more sexually than do women. This finding, which has been replicated in scores of studies using a variety of methodological approaches, has been linked to important social concerns, including sexual assault and sexual harassment. This article provides a critical review of the published literature on gender differences in sexual intent perception, using selective examples to illustrate and summarize the field’s major constructs, methodologies, and empirical findings. Theoretical explanations for gender differences in sexual intent perceptions are reviewed. Finally, we highlight the field’s remaining issues and make several recommendations for future research directions. PMID:19763282
-
[Sexuality of the elderly: a survey and management].
Ribes, G; Cour, F
2013-07-01
To evaluate sexuality in elderly couples and have the knowledge of its specific therapeutic options. Review of articles published on this subject in the Medline database, selected according to their scientific relevance together with a reflexion from our own experience. Due to increased life expectancy and the changes in society leading to a life with more than one consecutive partner, couples expect to continue sexual activity after the age of 65. Clinicians are asked to address this issue frequently. With age the frequency of genital sexual relations decreases. Sexual activity should be higher both for males and females. The quality of the relationship of the couple is a key element in maintaining sexual relations in this age group. Sexual satisfaction depends on the understanding, by both partners, of the physical and psychological changes due to increased age. The sexuality of the elderly couple must be analysed using specific criteria. The clinician's task is to explain to the patients the physiological change due to aging and give them advice on how to adapt their sexual behavior accordingly. Management will, at the same time, include pharmacological treatment, notably for erectile dysfunction, in order to restore satisfactory sexual relations. For women, vaginal lubrication products are essential. This global management should allow many elderly couples wishing to continue sexual relations, to enjoy this period of their lives in harmony with what they desire. Copyright © 2012 Elsevier Masson SAS. All rights reserved.
-
Oshri, Assaf; Tubman, Jonathan G; Morgan-Lopez, Antonio A; Saavedra, Lissette M; Csizmadia, Annamaria
2013-01-01
This study evaluated relations between sexual sensation seeking, co-occurring sex and alcohol use, and sexual risk behaviors (eg, unprotected intercourse and multiple sex partners) among adolescents receiving treatment for substance abuse problems. The ethnically diverse sample included 394 adolescents recruited from outpatient treatment (280 males; Mage = 16.33 years, SDage = 1.15). Structural equation modeling (SEM) was used to test direct and indirect paths between sexual sensation seeking and sexual risk behaviors via the frequency of co-occurring sex and alcohol use. Conditional indirect effects by gender were also tested. Analyses identified significant effects of sexual sensation seeking on co-occurring sex and alcohol use and sexual risk behaviors. The path from co-occurring sex and alcohol use to unprotected intercourse was significantly stronger among adolescent girls, suggesting a mediation effect moderated by gender. No gender difference was found for the indirect path from sexual sensation seeking and number of past year sexual partners via co-occurring sex and alcohol use. Selected prevention efforts are needed to promote HIV risk reduction among adolescents in substance abuse treatment. The documented conditional indirect effect for unprotected intercourse suggests that HIV prevention programs should pay special attention to gender-specific patterns of alcohol use and sexual risk behavior when tailoring program content. (Am J Addict 2013; 22:197-205). Copyright © American Academy of Addiction Psychiatry.
-
Sex, kings and serial killers and other group-selected human traits.
Bowles, J T
2000-06-01
(Note: This unorthodox paper contains the first argument for heart disease being a programmed age change and promoted by the dramatic, post age-40 increases in the hormones FSH and hCG seen in some individuals.) A recent issue of Science suggests that the evolutionary purpose of sex is unknown. Surviving to adulthood implies a valuable gene combination which is destroyed by sexual recombination. This should be detrimental to offspring. PROPOSED: Sex is group-selected in prey to allow coalescence of beneficial, and disposal of detrimental, mutations in single individuals enabling rapid adaptation to novel predation. Group selection is a universal force driven by local inter-species (not intra-species) competition. Aging, metabolism, litter size, and fixed body size are directly linked. Sexual recombination and chromosomes destroy gene linkage and exist because mutations are usually detrimental, rarely positive, and occur in linked groups. In unevolving environments, sex is selected against and asexuality emerges. Periodic evolution of novel predators, like man, can explain the 'punctuated equilibria' fossil record. Genes inhibited by methylation or chromatin condensation, expressed at older ages in predation-minimized environments, allow for group selection. Stress increases mutation rates and beneficial mutation likelihood. Females select bigger, brighter, louder, or stronger males that can survive predator attention. Size approximates age and thus predator encounters; male traits represent predation-survival potential. Human male traits include, balding, acne, beard-length, wrinkling, graying, nose/ear growth. Progeria accelerates development of most male traits. Domination of groups by single males allows rapid predation-defense evolution: adolescent males are expelled, brave the wild, and expel another group's male to mate. If expelled and dominant males are culled by predation, males reaching puberty first will reproduce. Hormonal acceleration of puberty
-
Higgs, Tamsin; Carter, Adam J; Stefanska, Ewa B; Glorney, Emily
2017-08-01
Establishing a model of sexual assault reflecting psychosocial and behavioral characteristics of perpetrators of sexual killing and rape is necessary for development in risk assessment and intervention. Methodological variations in defining sexual killing have amalgamated serial and non-serial offenders and perpetrators with direct and indirect associations between killing and sexual arousal. This study defined sexual killing specifying that killing should be directly linked to sexual arousal, and sampled 48 sexual killers, operationalized to include only those engaging in post-mortem sexual interference, with one or two known female victims (non-serial), from prison service national (England and Wales) databases. These sexual killers were compared with 48 non-homicide, life or indeterminately sentenced sexual aggressors on psychological and crime scene characteristics. Contrary to previous research, fatal outcomes were associated with neither stranger victims nor weapon presence; sexual killing was characterized by severity of violence less so than non-fatal assault. Sexual killers more often reported problems with emotional loneliness, empathic concern, and sexual entitlement than the sexual aggressors. Theoretical and applied implications are discussed.
-
An epidemiological study of sexual disorders in south Indian rural population
Sathyanarayana Rao, T. S.; Darshan, M. S.; Tandon, Abhinav
2015-01-01
Background: Sexuality is an important aspect of the personality of an individual and influences psychological, physical and social well-being of both men and women. It is a paradox, that in the country where ?kamasutra? (by Vatsyayana) took birth, there is a lack of research publications and sexuality related literature; hence the current study was conducted, to estimate the prevalence and association of sexual disorders with various socio-demographic variables, in the selected rural populati...
-
Cole, Jennifer; Sprang, Ginny; Lee, Robert; Cohen, Judith
2016-01-01
This study examined the demographic features, trauma profiles, clinical severity indicators, problem behaviors, and service utilization characteristics of youth victims of commercial sexual exploitation (CSE) compared with a matched sample of sexually abused/assaulted youth who were not exploited in commercial sex. Secondary data analysis and propensity score matching were used to select a sample of 215 help-seeking youth who were exploited in prostitution (n = 43) or who were sexually abused/assaulted but not exploited in prostitution (n = 172) from the National Child Traumatic Stress Network Core Data Set (NCTSN CDS). Propensity Score Matching was used to select a comparison sample based on age, race, ethnicity, and primary residence. Statistically significant differences were noted between the groups on standardized (e.g., UCLA Posttraumatic Stress Disorder Reaction Index [PTSD-RI], Child Behavior Checklist [CBCL]) and other measures of emotional and behavioral problems (e.g., avoidance and hyperarousal symptoms, dissociation, truancy, running away, conduct disorder, sexualized behaviors, and substance abuse). This study provides useful insight into the symptom and service utilization profiles of youth exploited in commercial sex as compared with youth with other types of sexually exploitive experiences. Targeted screening and event-sensitive measures are recommended to more accurately identify youth exploited in commercial sex. More research is needed to determine if and what modifications to trauma therapies may be required to address the more severe symptomatology and behavior problems associated with youth exploited in commercial sex. © The Author(s) 2014.
-
Sex Attracts: Investigating Individual Differences in Attentional Bias to Sexual Stimuli
Kagerer, Sabine; Wehrum, Sina; Klucken, Tim; Walter, Bertram; Vaitl, Dieter; Stark, Rudolf
2014-01-01
We investigated the impact of sexual stimuli and the influence of sexual motivation on the performance in a dot-probe task and a line-orientation task in a large sample of males and females. All pictures (neutral, erotic) were rated on the dimensions of valence, arousal, disgust, and sexual arousal. Additionally, questionnaires measuring sexual interest/desire/motivation were employed. The ratings of the sexual stimuli point to a successful picture selection because sexual arousal did not differ between the sexes. The stimuli were equally arousing for men and women. Higher scores in the employed questionnaires measuring sexual interest/desire/motivation led to higher sexual arousal ratings of the sex pictures. Attentional bias towards sex pictures was observed in both experimental tasks. The attentional biases measured by the dot-probe and the line-orientation task were moderately intercorrelated suggesting attentional bias as a possible marker for a sex-attention trait. Finally, only the sexual sensation seeking score correlated with the attentional biases of the two tasks. Future research is needed to increase the predictive power of these indirect measures of sexual interest. PMID:25238545
-
Antidepressant induced sexual dysfunction Part 1: epidemiology ...
African Journals Online (AJOL)
Adele
Abstract. Sexual dysfunction is a common side effect of treatment with antidepressants, particularly those with a predominantly .... free of serotonergic effects or have highly selective receptor .... received little attention in the current literature.
-
Clarke, Juanne
2009-05-01
The purpose of this paper is to report on an exploratory content analysis of the portrayal of sexuality, sexual health and disease in select magazines designed for two groups of women: teenagers and women in the 40-50-year-old age category in the USA. The analysis found that magazine portrayal was both similar for the two groups of women and distinctly different. Neither group of magazines focused on women's sexual desire. Both kinds of magazines emphasized that it was women's work and worry to control sexual expression. Teenagers were described as responsible for avoiding sex in order to prevent pregnancy, fearsomely described STIs and untrustworthy male sexual partners. Abstinence was presented as the only viable option for young women. Women in the 40-50-year-old age group were portrayed as responsible for the emotion work and sexual relations linked to their responsibility for maintaining their marriages and fulfilling their tasks of motherhood, especially through the monitoring of the sexuality of their female children. Sex was characterized in terms akin to women's work within the home. Possible explanations for, and consequences of, these presentations of sexuality are discussed.
-
Peixoto, Maria Manuela; Nobre, Pedro
2017-04-01
Despite the existence of conceptual models of sexual dysfunction based on cognitive theory, few studies have tested the role of vulnerability factors such as sexual beliefs as moderators of the activation of cognitive schemas in response to negative sexual events. To test the moderator role of dysfunctional sexual beliefs in the association between the frequency of negative sexual episodes and the activation of incompetence schemas in gay and heterosexual men. Five-hundred seventy-five men (287 gay, 288 heterosexual) who completed an online survey on cognitive-affective dimensions and sexual functioning were selected from a larger database. Hierarchical regression analyses were conducted to test the hypothesis that dysfunctional sexual beliefs moderate the association between the frequency of unsuccessful sexual episodes and the activation of incompetence schemas. Participants completed the Sexual Dysfunctional Beliefs Questionnaire and the Questionnaire of Cognitive Schemas Activated in Sexual Context. Findings indicated that men's ability for always being ready for sex, to satisfy the partner, and to maintain an erection until ending sexual activity constitute "macho" beliefs that moderate the activation of incompetence schemas when unsuccessful sexual events occur in gay and heterosexual men. In addition, activation of incompetence schemas in response to negative sexual events in gay men was moderated by the endorsement of conservative attitudes toward moderate sexuality. The main findings suggested that psychological interventions targeting dysfunctional sexual beliefs could help de-catastrophize the consequences of negative sexual events and facilitate sexual functioning. Despite being a web-based study, it represents the first attempt to test the moderator role of dysfunctional sexual beliefs in the association between the frequency of unsuccessful sexual episodes and the activation of incompetence schemas in gay and heterosexual men. Overall, findings
-
Directory of Open Access Journals (Sweden)
Guilherme Vanoni Polanczyk
2003-02-01
Full Text Available OBJETIVO: Verificar a prevalência da exposição à violência sexual entre adolescentes estudantes de escolas estaduais. MÉTODOS: Foram selecionadas 52 escolas estaduais de Porto Alegre, RS, Brasil, com ensino fundamental completo, por meio de um processo de amostragem aleatória, estratificada de acordo com o tamanho das escolas. Foi selecionada, em cada escola, uma turma de oitava série por sorteio aleatório e foram incluídos todos os adolescentes presentes nas salas de aula que consentiram em participar do estudo. Foi utilizado o instrumento Triagem da Exposição de Crianças à Violência na Comunidade para identificar jovens que foram vítimas, testemunhas ou que conheciam vítimas de atos de violência sexual. RESULTADOS: Foram incluídos 1.193 adolescentes, representando 10,3% dos alunos matriculados na oitava série da rede estadual da cidade. Vinte e sete (2,3% adolescentes relataram ter sido vítimas de violência sexual, 54 (4,5% ter sido testemunhas de algum tipo de violência sexual e 332 (27,9% relataram conhecer alguém que tenha sido vítima de violência sexual. CONCLUSÕES: A exposição à violência sexual pelas três formas de contato relatadas mostrou-se freqüente entre os adolescentes estudados. São necessários estudos que abordem a violência sexual como um fenômeno social amplo, com múltiplos fatores associados, amparando estratégias comunitárias de prevenção e de tratamento.OBJECTIVE: To assess the prevalence o sexual violence among adolescents of public schools. METHODS: Fifty-two public elementary schools of Porto Alegre, Brazil, were selected through random sampling stratified by school size. An 8th grade class was selected in each school through simple random sampling and all adolescents attending the classes who agreed to participate were included in the study. The Screening Survey of Children's Exposure to Community Violence was used to identify adolescents who were victims, witnesses or knew
-
Overbeek, Geertjan; van de Bongardt, Daphne; Baams, Laura
2018-03-13
One main source of sexual socialization lies within family interactions. Especially sexuality-specific parenting may determine adolescents' sexual development-adolescents' sexual behavior and sexual risk behavior, sexualized media consumption and permissive sexual attitudes-to a significant extent, but different ideas exist about how this works. In this longitudinal study, we examined two hypotheses on how sexuality-specific parenting-parenting aimed specifically at children's sexual attitudes and behaviors-relates to adolescents' sexual development. A first buffer hypothesis states that parents' instructive media discussions with their children-called instructive mediation-buffers the effect of sexualized media consumption on adolescents' sexual attitudes and behavior and, vice versa, the effect of adolescents' sexual attitudes and behavior on sexualized media consumption. A second brake hypothesis states that parents, by communicating love-and-respect oriented sexual norms, slow down adolescents' development toward increased sexualized media use, permissive sexual attitudes, and sexual behavior and sexual risk behavior. Using four-wave longitudinal data from 514 Dutch adolescents aged 13-16 years (49.8% female), we found evidence to support a brake effect. More frequent parental communication of love-and-respect oriented sexual norms was associated with less permissive sexual attitudes and, for boys, with less advanced sexual behavior and a less rapid increase in sexual risk behavior. Parents' instructive mediation regarding adolescents' sexualized media consumption was associated with less permissive sexual attitudes at baseline, but only for girls. No systematic evidence emerged for a buffer effect of parents' instructive mediation. In conclusion, although our data seem to suggest that parent-child communication about sex is oftentimes "after the fact", we also find that more directive parental communication that conveys love-and-respect oriented sexual norms
-
DEFF Research Database (Denmark)
Colchero, Fernando; Aliaga, Alix Eva; Jones, Owen
2017-01-01
in shaping demographic trajectories in wild populations. The link between these two processes has seldom been explored. 2. We used Bayesian survival trajectory analysis to study age-specific mortality trajectories in the Eurasian sparrowhawk (Accipiter nisus), a monogamous raptor with reversed sexual size...... driven by the differences in individual heterogeneity between the two sexes. Females were more heterogeneous than males in their level of frailty. Thus, a larger number of females with low frailty are able to survive to older ages than males, with life expectancy for the least frail adult females....... Although we found that variables that relate to the cost of reproduction and sexual dimorphism are at least partially involved in determing these sex differences, it is through their effect on the level of frailty that they affect age patterns of mortality. Therefore, our results raise the possibility...
-
Udaka, Hiroko; Ueda, Chiaki; Goto, Shin G
2010-12-01
In this study, we investigated the physiological mechanisms underlying temperature tolerance using Drosophila melanogaster lines with rapid, intermediate, or slow recovery from heat or chill coma that were established by artificial selection or by free recombination without selection. Specifically, we focused on the relationships among their recovery from heat or chill coma, survival after severe heat or cold, and survival enhanced by rapid cold hardening (RCH) or heat hardening. The recovery time from heat coma was not related to the survival rate after severe heat. The line with rapid recovery from chill coma showed a higher survival rate after severe cold exposure, and therefore the same mechanisms are likely to underlie these phenotypes. The recovery time from chill coma and survival rate after severe cold were unrelated to RCH-enhanced survival. We also examined the expression of two genes, Heat-shock protein 70 (Hsp70) and Frost, in these lines to understand the contribution of these stress-inducible genes to intraspecific variation in recovery from temperature coma. The line showing rapid recovery from heat coma did not exhibit higher expression of Hsp70 and Frost. In addition, Hsp70 and Frost transcription levels were not correlated with the recovery time from chill coma. Thus, Hsp70 and Frost transcriptional regulation was not involved in the intraspecific variation in recovery from temperature coma. Copyright © 2010 Elsevier Ltd. All rights reserved.
-
Mutual ornamentation, sexual selection, and social dominance in the black swan
Kraaijeveld, K; Gregurke, J; Hall, C; Komdeur, J; Mulder, RA
We investigated the adaptive significance of a sexually monomorphic ornament in the black swan Cygnus atratus. Both sexes grow curled feathers on their wings (range 7-22 curled feathers per wing), which are displayed prominently in a range of social interactions. The number of curled feathers
-
Gaioso, Vanessa Pirani; Villarruel, Antonia Maria; Wilson, Lynda Anne; Azuero, Andres; Childs, Gwendolyn Denice; Davies, Susan Lane
2015-01-01
to test a theoretical model based on the Parent-Based Expansion of the Theory of Planned Behavior examining relation between selected parental, teenager and cultural variables and Latino teenagers' intentions to engage in sexual behavior. a cross-sectional correlational design based on a secondary data analysis of 130 Latino parent and teenager dyads. regression and path analysis procedures were used to test seven hypotheses and the results demonstrated partial support for the model. Parent familism and knowledge about sex were significantly associated with parents' attitudes toward sexual communication with their teenagers. Parent Latino acculturation was negatively associated with parents' self-efficacy toward sexual communication with their teenagers and positevely associated with parents' subjective norms toward sexual communication with their teenagers. Teenager knowledge about sex was significantly associated with higher levels of teenagers' attitudes and subjective norms about sexual communication with parents. Only the predictor of teenagers' attitudes toward having sex in the next 3 months was significantly associated with teenagers' intentions to have sex in the next 3 months. the results of this study provide important information to guide future research that can inform development of interventions to prevent risky teenager sexual behavior among Latinos.
-
Female sexual arousal: genital anatomy and orgasm in intercourse.
Wallen, Kim; Lloyd, Elisabeth A
2011-05-01
In men and women sexual arousal culminates in orgasm, with female orgasm solely from sexual intercourse often regarded as a unique feature of human sexuality. However, orgasm from sexual intercourse occurs more reliably in men than in women, likely reflecting the different types of physical stimulation men and women require for orgasm. In men, orgasms are under strong selective pressure as orgasms are coupled with ejaculation and thus contribute to male reproductive success. By contrast, women's orgasms in intercourse are highly variable and are under little selective pressure as they are not a reproductive necessity. The proximal mechanisms producing variability in women's orgasms are little understood. In 1924 Marie Bonaparte proposed that a shorter distance between a woman's clitoris and her urethral meatus (CUMD) increased her likelihood of experiencing orgasm in intercourse. She based this on her published data that were never statistically analyzed. In 1940 Landis and colleagues published similar data suggesting the same relationship, but these data too were never fully analyzed. We analyzed raw data from these two studies and found that both demonstrate a strong inverse relationship between CUMD and orgasm during intercourse. Unresolved is whether this increased likelihood of orgasm with shorter CUMD reflects increased penile-clitoral contact during sexual intercourse or increased penile stimulation of internal aspects of the clitoris. CUMD likely reflects prenatal androgen exposure, with higher androgen levels producing larger distances. Thus these results suggest that women exposed to lower levels of prenatal androgens are more likely to experience orgasm during sexual intercourse. Copyright © 2011. Published by Elsevier Inc.
-
Sexual education, gender ideology, and youth sexual empowerment.
Grose, Rose Grace; Grabe, Shelly; Kohfeldt, Danielle
2014-01-01
Sexual education plays an essential role in preventing unplanned pregnancy and the transmission of sexually transmitted infections (STIs). School-based sexual education programs, in particular, may be well positioned to address social factors that are empirically linked to negative sexual health outcomes, such as traditional social norms surrounding gender and sexuality. However, youth are seldom granted access to sexual education programs that explicitly address these issues. This study presents findings from a pretest-posttest survey of a sexual education program that did. It was designed for eighth graders (N=95) in the context of a school-community collaboration. The study assessed the links between several components of sexual empowerment, including gender ideology, sexual knowledge, and contraceptive beliefs. Findings link participation in the sexual education program to more progressive attitudes toward girls and women, less agreement with hegemonic masculinity ideology, and increases in sexual health and resource knowledge. Structural equation models suggest that traditional attitudes toward women were significantly related to hegemonic masculinity ideology among both boys and girls, which was in turn negatively related to safer contraceptive beliefs.
-
Oberg, C J; Moyes, L V; Domek, M J; Brothersen, C; McMahon, D J
2011-05-01
Various selective media for enumerating probiotic and cheese cultures were screened, with 6 media then used to study survival of probiotic bacteria in full-fat and low-fat Cheddar cheese. Commercial strains of Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus paracasei, or Bifidobacterium lactis were added as probiotic adjuncts. The selective media, designed to promote growth of certain lactic acid bacteria (LAB) over others or to differentiate between LAB, were used to detect individual LAB types during cheese storage. Commercial strains of Lactococcus, Lactobacillus, and Bifidobacterium spp. were initially screened on the 6 selective media along with nonstarter LAB (NSLAB) isolates. The microbial flora of the cheeses was analyzed during 9 mo of storage at 6°C. Many NSLAB were able to grow on media presumed selective for Lactococcus, Bifidobacterium spp., or Lb. acidophilus, which became apparent after 90 d of cheese storage, Between 90 and 120 d of storage, bacterial counts changed on media selective for Bifidobacterium spp., suggesting growth of NSLAB. Appearance of NSLAB on Lb. casei selective media [de man, Rogosa, and Sharpe (MRS)+vancomycin] occurred sooner (30 d) in low-fat cheese than in full-fat control cheeses. Differentiation between NSLAB and Lactococcus was achieved by counting after 18 to 24h when the NSLAB colonies were only pinpoint in size. Growth of NSLAB on the various selective media during aging means that probiotic adjunct cultures added during cheesemaking can only be enumerated with confidence on selective media for up to 3 or 4 mo. After this time, growth of NSLAB obfuscates enumeration of probiotic adjuncts. When adjunct Lb. casei or Lb. paracasei cultures are added during cheesemaking, they appear to remain at high numbers for a long time (9 mo) when counted on MRS+vancomycin medium, but a reasonable probability exists that they have been overtaken by NSLAB, which also grow readily on this medium. Enumeration using multiple
-
Sexual dimorphism of head morphology in three-spined stickleback Gasterosteus aculeatus.
Aguirre, W E; Akinpelu, O
2010-09-01
This study examined sexual dimorphism of head morphology in the ecologically diverse three-spined stickleback Gasterosteus aculeatus. Male G. aculeatus had longer heads than female G. aculeatus in all 10 anadromous, stream and lake populations examined, and head length growth rates were significantly higher in males in half of the populations sampled, indicating that differences in head size increased with body size in many populations. Despite consistently larger heads in males, there was significant variation in size-adjusted head length among populations, suggesting that the relationship between head length and body length was flexible. Inter-population differences in head length were correlated between sexes, thus population-level factors influenced head length in both sexes despite the sexual dimorphism present. Head shape variation between lake and anadromous populations was greater than that between sexes. The common divergence in head shape between sexes across populations was about twice as important as the sexual dimorphism unique to each population. Finally, much of the sexual dimorphism in head length was due to divergence in the anterior region of the head, where the primary trophic structures were found. It is unclear whether the sexual dimorphism was due to natural selection for niche divergence between sexes or sexual selection. This study improves knowledge of the magnitude, growth rate divergence, inter-population variation and location of sexual dimorphism in G. aculeatus head morphology. © 2010 The Authors. Journal compilation © 2010 The Fisheries Society of the British Isles.
-
Correlates of sexual initiation among European adolescents.
Directory of Open Access Journals (Sweden)
Pietro Gambadauro
Full Text Available Sexuality is a physiological component of adolescent development, though early initiation is associated with reproductive health risk. This study aimed at identifying correlates and predictors of sexual initiation in a large multinational cohort of European adolescents.A questionnaire addressing socio-demographics, behaviours, mental health and sexual activity, was delivered to 11,110 adolescents recruited from 168 randomly selected schools in 10 European countries between 2009 and 2011. A follow-up questionnaire was delivered after 12 months. The longitudinal association of baseline risk behaviors, psychological attributes and contextual vulnerabilities, with sexual initiation during follow-up was evaluated through simple and multivariable age/sex stratified logistic regression. Multinomial logistic regression measured the association between predictors and sexual initiation with or without coexisting reproductive risk factors, such as multiple partners or infrequent condom use.Baseline sexual experience was reported by 19.2% of 10,757 respondents (median age 15; IQR 14-15; females 59.6%. This was significantly more frequent among pupils older than 15 (41% and males (20.8%. Of 7,111 pupils without previous experience who were available at follow-up (response rate 81.8%, 17% reported sexual initiation, without differences between females and males. Baseline smoking (age/sex adjusted odds ratio [aOR] 3.63, alcohol use (aOR 2.95, illegal drugs use (aOR 2.72, and poor sleep (aOR 1.71 predicted sexual initiation. Stratified analyses showed a particularly strong association in case of younger and female pupils, and, among girls, when initiation was reported together with multiple partners and/or infrequent condom use. Externalizing (i.e. conduct and hyperactivity symptoms independently predicted sexual initiation. Internalizing difficulties (i.e. emotional and peer problems were negatively associated with early and risky sexual initiation among boys
-
G.J. Overbeek (Geertjan); van de Bongardt, D. (Daphne); Baams, L. (Laura)
2018-01-01
textabstractOne main source of sexual socialization lies within family interactions. Especially sexuality-specific parenting may determine adolescents’ sexual development—adolescents’ sexual behavior and sexual risk behavior, sexualized media consumption and permissive sexual attitudes—to a
-
Overbeek, Geertjan; van de Bongardt, Daphne; Baams, Laura
2018-01-01
One main source of sexual socialization lies within family interactions. Especially sexuality-specific parenting may determine adolescents’ sexual development—adolescents’ sexual behavior and sexual risk behavior, sexualized media consumption and permissive sexual attitudes—to a significant extent,
-
Psychopathology and personality in juvenile sexual homicide offenders.
Myers, W C; Blashfield, R
1997-01-01
This project describes the psychopathology and personality findings in 14 juveniles who committed sexual homicide. These incarcerated youth were assessed using a structured interview, a personality assessment instrument, correctional files review, and an author-designed clinical interview. Nearly all of these youth met DSM-III-R conduct disorder criteria at the time of the crime. The presence of personality disorders and moderately high psychopathy scores at follow-up were common. Two-thirds of these youth reported the presence of violent sexual fantasies before their crimes. Weapons, most often knives, were used by these juvenile sexual murderers to kill known victims in a majority of the cases. They usually acted alone and selected a low risk victim. These findings suggest that juvenile sexual murderers are an emotionally and behaviorally disturbed population with identifiable psychopathology, personality disturbances, and criminal patterns.
-
Factors influencing fluoxetine-induced sexual dysfunction in female rats
Adams, Sarah; Heckard, Danyeal; Hassell, James; Uphouse, Lynda
2012-01-01
Treatment with selective serotonin reuptake inhibitors, such as fluoxetine, produces sexual side effects with low sexual desire being the most prevalent effect in females. In few studies have preclinical models for such antidepressant-induced sexual dysfunction been fruitful. In the current manuscript, the effects of fluoxetine on multiple measures of female sexual motivation and sexual receptivity were examined. Ovariectomized, Fischer rats were primed with 10 μg estradiol benzoate and 500 μg progesterone. Partner preference, active investigation of the male, and measures of sexual behavior were examined after injection with 15 mg/kg fluoxetine. Factors (pretesting for sexual behavior, size of the test arena, non-contact time with a male) that differ among experiments designed to study antidepressant-induced female rat sexual dysfunction were studied. The male preference ratio was not affected by fluoxetine treatment but active investigation of the male was reduced; lordosis behavior was inhibited and pretesting for sexual receptivity amplified fluoxetine's inhibition; size of the testing arena or non-contact experience with the male had no effect. Regardless of test condition, when given the opportunity to escape from the male, fluoxetine-treated females displayed escape behavior. Measures of male preference and active investigation, but not lordosis behavior, appeared to be affected by fluoxetine's impact on activity. The collective data provided a behavioral profile of fluoxetine-induced sexual dysfunction. These findings reinforce the value of multiple measures when attempting to model antidepressant-induced female sexual dysfunction. PMID:22835821
-
The reciprocal relationship between sexual victimization and sexual assertiveness.
Livingston, Jennifer A; Testa, Maria; VanZile-Tamsen, Carol
2007-03-01
Low sexual assertiveness has been proposed as a possible mechanism through which sexual revictimization occurs, yet evidence for this has been mixed. In this study, prospective path analysis was used to examine the relationship between sexual refusal assertiveness and sexual victimization over time among a community sample of women. Results provide support for a reciprocal relationship, with historical victimization predicting low sexual assertiveness and low sexual assertiveness predicting subsequent victimization. The effect of recent sexual victimization on subsequent sexual assertiveness also was replicated prospectively. These findings suggest that strengthening sexual assertiveness may help reduce vulnerability to future victimization.
-
Williams' paradox and the role of phenotypic plasticity in sexual systems.
Leonard, Janet L
2013-10-01
As George Williams pointed out in 1975, although evolutionary explanations, based on selection acting on individuals, have been developed for the advantages of simultaneous hermaphroditism, sequential hermaphroditism and gonochorism, none of these evolutionary explanations adequately explains the current distribution of these sexual systems within the Metazoa (Williams' Paradox). As Williams further pointed out, the current distribution of sexual systems is explained largely by phylogeny. Since 1975, we have made a great deal of empirical and theoretical progress in understanding sexual systems. However, we still lack a theory that explains the current distribution of sexual systems in animals and we do not understand the evolutionary transitions between hermaphroditism and gonochorism. Empirical data, collected over the past 40 years, demonstrate that gender may have more phenotypic plasticity than was previously realized. We know that not only sequential hermaphrodites, but also simultaneous hermaphrodites have phenotypic plasticity that alters sex allocation in response to social and environmental conditions. A focus on phenotypic plasticity suggests that one sees a continuum in animals between genetically determined gonochorism on the one hand and simultaneous hermaphroditism on the other, with various types of sequential hermaphroditism and environmental sex determination as points along the spectrum. Here I suggest that perhaps the reason we have been unable to resolve Williams' Paradox is because the problem was not correctly framed. First, because, for example, simultaneous hermaphroditism provides reproductive assurance or dioecy ensures outcrossing does not mean that there are no other evolutionary paths that can provide adaptive responses to those selective pressures. Second, perhaps the question we need to ask is: What selective forces favor increased versus reduced phenotypic plasticity in gender expression? It is time to begin to look at the question
-
The readability and suitability of sexual health promotion leaflets.
Corcoran, Nova; Ahmad, Fatuma
2016-02-01
To investigate the readability and suitability of sexual health promotion leaflets. Application of SMOG, FRY and SAM tests to assess the readability and suitability of a selection of sexual health leaflets. SMOG and FRY scores illustrate an average reading level of grade 9. SAM scores indicate that 59% of leaflets are superior in design and 41% are average in design. Leaflets generally perform well in the categories of content, literacy demand, typography and layout. They perform poorly in use of graphics, learning stimulation/motivation and cultural appropriateness. Sexual health leaflets have a reading level that is too high. Leaflets perform well on the suitability scores indicating they are reasonably suitable. There are a number of areas where sexual health leaflets could improve their design. Numerous practical techniques are suggested for improving the readability and suitability of sexual health leaflets. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
-
Nyokangi, Doris; Phasha, Nareadi
2016-05-01
This paper reports part of the findings of a study which exposed sexual violence in schools for learners with mild intellectual disability in South Africa. Special attention was paid on factors contributing to such a problem. Data were collected using focus groups and individual interviews with 16 learners with mild intellectual disability at two special schools in South Africa. This was followed by individual interviews with the school nurse and social worker, and an analysis of schools' books of incidents. Factors contributing to sexual violence at schools for learners with mild intellectual disability included: (i) peer pressure, (ii) concealment of reported incidents of sexual violence, (iii) unsupervised areas linked to schools and (iv) arranged relationships. The following suggestions are put forth: (i) awareness programmes, (ii) sensitization of teachers about the consequences and prevention of sexual violence, (iii) boundaries within which the arranged relationship occurs, (iv) intensification of sexuality education and (v) supervision around the school premises. © 2015 John Wiley & Sons Ltd.
-
[Impact of backward sexual viewpoints on population development].
Wang, B
1991-04-01
In the development of human society, the reproductive function was considered the sole purpose of sexual activities. Any other purposes were deemed abnormal or deviant. The prevalence of that viewpoint reflected the needs during the transformation from hunting to farming as major means of production of the society and the needs for large populations under the socioeconomic conditions of rural society. With the low level of productivity in a family-oriented economy, further development depended on the number of labor hands in the family. The wars for extension of territory and for survival need a constant supply of soldiers. Under such circumstances, the need for large populations implied the importance of fertility behavior in sexual relations. In the rural farming societies, fertility was important in strengthening and developing the family wealth, status, and family structure. Blood relations were emphasized in rural society for family inheritance, for expansion of family influence, and for old age support. The rapid decline of fertility in Europe at the beginning of this century was proposed by some Chinese scholars as the result of their citizens pursuing individual happiness including in sexual relations. The use of contraceptives prevented couples from being overburdened with children. These concepts on sexual relations facilitated the decline of fertility. The necessary social and economic conditions and advances in technology are already present for the changes of the traditional concepts toward sexual relations. The united efforts of social agencies in promoting these changes will be an efficient ensure in regulating the speed of population growth.
-
Sales, Jessica M.; Smearman, Erica; Brody, Gene H.; Milhausen, Robin; Philibert, Robert A.; DiClemente, Ralph J.
2013-01-01
Sexuality-related constructs such as sexual arousal, sexual sensation seeking (SSS) and sexual satisfaction have been related to sexual behaviors that place one at risk for adverse consequences such as sexually transmitted infections (STIs), HIV, and unintended pregnancy. The biopsychosocial model posits an array of factors, ranging from social environmental factors, biological, and psychological predispositions that may be associated with these sexuality constructs in adolescent samples. Afr...
-
Kilpimaa, Janne; Alatalo, Rauno V.; Siitari, Heli
2004-01-01
Good genes models of sexual selection assume that sexual advertisement is costly and thus the level of advertisement honestly reveals heritable viability. Recently it has been suggested that an important cost of sexual advertisement might be impairment of the functioning of the immune system. In this field experiment we investigated the possible trade-offs between immune function and sexual advertisement by manipulating both mating effort and activity of immune defence in male pied flycatcher...
-
Sexual trauma disclosure in clinical settings: addressing diversity.
Roberts, Sushma T; Watlington, Christina G; Nett, Sara D; Batten, Sonja V
2010-01-01
Although sexual trauma is an experience with wide prevalence, it remains difficult for many individuals to discuss this trauma openly with others. Disclosure of a sexual trauma history to a receptive individual can lead to both emotional and instrumental support. However, a myriad of factors related not only to current circumstances but also to cultural and individual differences determine whether an individual will choose to share his or her trauma history with someone else. Mental health clinicians may be more likely than many other people to be the recipients of a disclosure of sexual trauma. Thus, ensuring that clinicians show sensitivity to the role that diverse demographic and cultural factors can play in the process of disclosure is important to facilitating a thoughtful and productive response to such an event. The current article reviews a segment of the literature on disclosure of sexual assault and focuses on selected diversity domains (i.e., nonheterosexual orientation, age, gender, and race) that may impact the disclosure of sexual assault. Practical suggestions are proposed to assist clinicians in assessing sexual trauma and facilitating disclosure in a culturally competent manner.
-
Sexual arousal and rhythmic synchronization: A possible effect of vasopressin
DEFF Research Database (Denmark)
Miani, Alessandro
2016-01-01
Music is ubiquitous. Yet, its biological relevance is still an ongoing debate. Supporting the view that music had an ancestral role in courtship displays, a pilot study presented here provides preliminary evidence on the link between music and sexual selection. The underlying hypothesis is based...... by vasopressin and its genes. Hence, to test this hypothesis, a rhythmic synchronization task was employed here on one male subject during sexual arousal. Results revealed a significant effect of sexual arousal on rhythm synchronization. This is the first report that empirically supports the hypothesis...
-
Sümer, Zeynep Hatipoğlu
2015-12-01
The purpose of this study is to examine the role of gender, religiosity, sexual activity, and sexual knowledge in predicting attitudes toward controversial aspects of sexuality among Turkish university students. Participants were 162 female and 135 male undergraduate students who were recruited on a volunteer basis from an urban state university in Turkey. The SKAT-A Attitude Scale along with background information form, sexual activities inventory, and sexual knowledge scale were administered to the participants. Simultaneous multiple regression analyses revealed that religiosity, particularly attendance to religious services was the most significant predictor in explaining university students' attitudes toward masturbation, abortion, homosexuality, pornography, and sexual coercion.
-
Zerubavel, Noga; Messman-Moore, Terri L
2013-12-01
The current study examined sexual victimization and two barriers to young women's sexual assertiveness: fear of sexual powerlessness and cognitive emotion dysregulation. College women (N = 499) responded to surveys and indicated that fear of sexual powerlessness and, to a lesser extent, cognitive emotion dysregulation were barriers to sexual assertiveness. Compared with nonvictims, sexually victimized women had greater problems with sexual assertiveness, fear of sexual powerlessness, and cognitive emotion dysregulation. Among victims, fear of sexual powerlessness and emotion dysregulation interacted to impede sexual assertiveness. Findings support targeting identified barriers in interventions to improve sexual assertiveness and reduce risk for unwanted sexual experiences and sexual victimization.
-
International Nuclear Information System (INIS)
Yuval, B.; Maor, M.; Levy, K.; Kaspi, R.; Taylor, P.; Shelly, T.
2007-01-01
The sterile insect technique (SIT) is increasingly being used around the world to control Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), the Mediterranean fruit fly as part of an area-wide integrated approach. One option that may improve the effectiveness of the SIT, by increasing the sexual competitiveness of released sterile males, consists of feeding males protein during the post-teneral stage, a diet that increases sexual performance of wild males. We examine the effects of diet on the successive hurdles males must overcome in order to inseminate females, i.e., joining leks, copulating females, having their sperm stored and inhibition of female remating. In addition, we address the effects of diet on post-release foraging success, longevity, and the ability to withstand starvation. While protein feeding universally increases the sexual success of wild males, its effect on sterile males varies with strain, experimental settings, and environmental conditions. In some cases, treatments that resulted in the best sexual performance were significantly associated with increased vulnerability to starvation. However, no particular diet affected the ability of sterile males to find nutrients in the field when these where available. We suggest it may be better to release relatively short-lived flies that are highly competitive, rather than long-lived, sexually ineffective ones. (author) [es
-
Teachers' Perspectives on Sexual and Reproductive Health ...
African Journals Online (AJOL)
AJRH Managing Editor
While school-based sexual and reproductive health interventions for in-school adolescents is widely recognized .... selection of the schools in Ile-Ife and Ilesa through .... abortion, which had led to deaths of some female ..... Indian journal of.
-
Human Sexual Conflict from Molecules to Culture
Directory of Open Access Journals (Sweden)
Gregory Gorelik
2011-10-01
Full Text Available Coevolutionary arms races between males and females have equipped both sexes with mutually manipulative and defensive adaptations. These adaptations function to benefit individual reproductive interests at the cost of the reproductive interests of opposite-sex mates, and arise from evolutionary dynamics such as parental investment (unequal reproductive costs between the sexes and sexual selection (unequal access to opposite-sex mates. Individuals use these adaptations to hijack others' reproductive systems, psychological states, and behaviors—essentially using other individuals as extended phenotypes of themselves. Such extended phenotypic manipulation of sexual rivals and opposite-sex mates is enacted by humans with the aid of hormones, pheromones, neurotransmitters, emotions, language, mind-altering substances, social institutions, technologies, and ideologies. Furthermore, sexual conflict may be experienced at an individual level when maternal genes and paternal genes are in conflict within an organism. Sexual conflict may be physically and emotionally destructive, but may also be exciting and constructive for relationships. By extending the biological concept of sexual conflict into social and cultural domains, scholars may successfully bridge many of the interdisciplinary gaps that separate the sciences from the humanities.
-
Sex attracts: investigating individual differences in attentional bias to sexual stimuli.
Directory of Open Access Journals (Sweden)
Sabine Kagerer
Full Text Available We investigated the impact of sexual stimuli and the influence of sexual motivation on the performance in a dot-probe task and a line-orientation task in a large sample of males and females. All pictures (neutral, erotic were rated on the dimensions of valence, arousal, disgust, and sexual arousal. Additionally, questionnaires measuring sexual interest/desire/motivation were employed. The ratings of the sexual stimuli point to a successful picture selection because sexual arousal did not differ between the sexes. The stimuli were equally arousing for men and women. Higher scores in the employed questionnaires measuring sexual interest/desire/motivation led to higher sexual arousal ratings of the sex pictures. Attentional bias towards sex pictures was observed in both experimental tasks. The attentional biases measured by the dot-probe and the line-orientation task were moderately intercorrelated suggesting attentional bias as a possible marker for a sex-attention trait. Finally, only the sexual sensation seeking score correlated with the attentional biases of the two tasks. Future research is needed to increase the predictive power of these indirect measures of sexual interest.
-
Beech, Anthony R; Mitchell, Ian J
2005-02-01
This paper describes what is currently known about attachment from the development, social-cognitive and biological literatures and outlines the impact on organisms given adverse development experiences that can have an effect upon attachment formation in childhood across these three literatures. We then describe the effects that 'insecure' attachment styles arising in childhood can affect brain chemistry and brain function and subsequently adult social/romantic relationships. In the paper, we note that a number of sexual offenders report adverse childhood experiences and that they possess attachment styles that, taken together, make it likely that they will either seek out intimate attachments in ways where they will have sex with children, perhaps confusing sex with intimacy or in aggressive ways as particularly happens with men who sexually assault adult women. The last section of the paper describes chemical treatment for sexual offenders, focusing on the use of selective serotonin re-uptake inhibitors (SSRIs). We note evidence for the role of SSRIs in promoting more social/affiliative behaviors and speculate on the effects that SSRIs have in the treatment of sexual offenders by targeting areas of the social brain. Here, we would argue that it would be useful to carry out treatment where there is a combination of SSRI treatment (to promote more prosocial feelings and behaviors) in conjunction with therapy that typically addresses thoughts and behaviors, i.e., cognitive-behavioral therapy/schema-focused therapy.
-
Depression and Liver Transplant Survival.
Meller, William; Welle, Nicole; Sutley, Kristen; Thurber, Steven
Patients who underwent liver transplantation and experienced clinical depression have heretofore evinced lower survival rates when compared to nondepressed counterparts. To investigate the hypothesis that transplant patients who seek and obtain medical treatment for depression would circumvent the prior reduced survival findings. A total of 765 patients with liver transplants were scrutinized for complications following transplantation. Further, 104 patients experienced posttransplant depression as manifested by diagnosis and treatment by medical personnel. Survival analyses were conducted comparing hazard and survival curves for these selected individuals and the remainder of transplant patients. Contrary to prior data and consistent with the aforementioned hypothesis, median survival durations, survival curves, and hazard functions (controlling for age and prolonged posttransplant survival for the depressed patients were better. The improved survival for the depressed patients may simply be related to an amelioration of depressed symptoms via antidepressant medications. However, this interpretation would only be congruent with reduced hazard, not elevated survival, beyond the norm (median) for other transplant participants. Assuming the reliability and generalization of our findings, perhaps a reasonable and compelling interpretation is that combined with the effectiveness of antidepressant medications, the seeking and receiving treatment for depression is a type of proxy measure of a more global pattern of adherence to recommended posttransplant medical regimens. Copyright © 2017 The Academy of Psychosomatic Medicine. Published by Elsevier Inc. All rights reserved.
-
Sexual behavior of single adult American women.
Duberstein Lindberg, Laura; Singh, Susheela
2008-03-01
Public policies promoting abstinence until marriage attempt to influence the sexual behavior of the more than 18 million American women who are currently single. An analysis of these women's behavior is needed to inform policies that are responsive to their sexual and reproductive health needs. Sexual behaviors, risk factors and reproductive health needs were examined among a nationally representative sample of 6,493 women aged 20-44 from the 2002 National Survey of Family Growth. Paired t tests were used to assess differences among single, married and cohabiting women by selected demographic, behavioral and risk measures. Thirty-six percent of women aged 20-44 are single, and nine in 10 single women are sexually experienced. Seventy percent of the latter women are currently sexually active; on average, they had intercourse in seven of the last 12 months. A higher proportion of single women (22%) than of cohabiting (9%) or married women (2%) have had two or more partners in the past year, and half of single women are at risk of unintended pregnancy. Furthermore, single women and cohabiting women are more likely to lack health insurance than are married women (21-25% vs. 12%). Because of the high level of sexual activity among single adult women, providers must address their reproductive health care needs and offer appropriate counseling and services. Government policies aimed at encouraging adult women to have sex only within marriage appear out of touch with the reality of the sexual behavior of single women.
-
Mechanisms of rapid sympatric speciation by sex reversal and sexual selection in cichlid fish.
Lande, R; Seehausen, O; van Alphen, J J
2001-01-01
Mechanisms of speciation in cichlid fish were investigated by analyzing population genetic models of sexual selection on sex-determining genes associated with color polymorphisms. The models are based on a combination of laboratory experiments and field observations on the ecology, male and female mating behavior, and inheritance of sex-determination and color polymorphisms. The models explain why sex-reversal genes that change males into females tend to be X-linked and associated with novel colors, using the hypothesis of restricted recombination on the sex chromosomes, as suggested by previous theory on the evolution of recombination. The models reveal multiple pathways for rapid sympatric speciation through the origin of novel color morphs with strong assortative mating that incorporate both sex-reversal and suppressor genes. Despite the lack of geographic isolation or ecological differentiation, the new species coexists with the ancestral species either temporarily or indefinitely. These results may help to explain different patterns and rates of speciation among groups of cichlids, in particular the explosive diversification of rock-dwelling haplochromine cichlids.
-
Correlates of sexual violence among adolescent females in Riyadh, Saudi Arabia.
Al-Quaiz, Al-Joharah M; Raheel, Hafsa M
2009-06-01
To determine the frequency, experiences and correlates of sexual violence among female adolescents in Riyadh city, Kingdom of Saudi Arabia. A cross-sectional survey was conducted in 2 schools in Riyadh city for adolescent females starting from January 2008 for 3 months. Five classes with 25 students in each were randomly selected from intermediate and secondary grade of each school. Four hundred and nineteen students were included. A self-answering questionnaire was distributed and collected after 15 minutes by 3 research assistants. Forty-two adolescent students (10%) were exposed to sexual violence. Only 31% of the students were taught how to react to sexual violence. Students whose order was > or = 5th among siblings and who had unsupportive parents in discussing sexual issues were more exposed to sexual violence (chi2=4.02, p=0.044, chi2=4.24, p=0.039). Being > or = 5th in order among siblings and having unsupportive parents in discussing sexual issues were correlates for exposure to sexual violence.
-
Subjective sleep quality, unstimulated sexual arousal, and sexual frequency
Directory of Open Access Journals (Sweden)
Rui Costa
Full Text Available Introduction: REM sleep deprivation increases unstimulated erections in rats, and total sleep deprivation increases erections during audiovisual sexual stimulation in men, but the effects of sleep problems on human unstimulated sexual arousal are unknown. Objective: We examined the associations of subjective sleep quality with unstimulated sexual arousal, satisfaction with sex life, and sexual frequency and desire over the past month. Methods: 275 Portuguese (169 women reported their anxiety, sexual arousal and sexual desire during a resting state, and completed the Pittsburgh Sleep Quality Index, the sexual satisfaction subscale of the LiSat scale, the Desire dimensions of the Female Sexual Function Index (women only and International Index of Erectile Function (men only. They additionally reported how many days in the past month they engaged in penile-vaginal intercourse, noncoital sex, and masturbation. Salivary testosterone (T was assayed by luminescence immunoassays. Results: Poorer sleep quality correlated with greater unstimulated sexual arousal in men with higher T levels and in women with higher T levels not taking oral contraceptives. In women with lower T, poorer subjective sleep quality correlated with greater sexual dissatisfaction. In both sexes, sleep quality was uncorrelated with sexual desire and sexual frequency over the past month. Discussion: Consistently with other studies in humans and animals, the findings are congruent with the notion that lack of sleep can increase sexual arousal, but not sexual frequency. T might play a role in the sexual arousal caused by lack of appropriate sleep.
-
Multidimensional sexual perfectionism.
Stoeber, Joachim; Harvey, Laura N; Almeida, Isabel; Lyons, Emma
2013-11-01
Perfectionism is a multidimensional personality characteristic that can affect all areas of life. This article presents the first systematic investigation of multidimensional perfectionism in the domain of sexuality exploring the unique relationships that different forms of sexual perfectionism show with positive and negative aspects of sexuality. A sample of 272 university students (52 male, 220 female) completed measures of four forms of sexual perfectionism: self-oriented, partner-oriented, partner-prescribed, and socially prescribed. In addition, they completed measures of sexual esteem, sexual self-efficacy, sexual optimism, sex life satisfaction (capturing positive aspects of sexuality) and sexual problem self-blame, sexual anxiety, sexual depression, and negative sexual perfectionism cognitions during sex (capturing negative aspects). Results showed unique patterns of relationships for the four forms of sexual perfectionism, suggesting that partner-prescribed and socially prescribed sexual perfectionism are maladaptive forms of sexual perfectionism associated with negative aspects of sexuality whereas self-oriented and partner-oriented sexual perfectionism emerged as ambivalent forms associated with positive and negative aspects.
-
A lover or a fighter? Opposing sexual selection pressures on men’s vocal pitch and facial hair
Mackey, Lauren L.; McCarty, Kristofor; Neave, Nick
2016-01-01
The traditional assumption within the research literature on human sexually dimorphic traits has been that many sex differences have arisen from intersexual selection. More recently, however, there has been a shift toward the idea that many male features, including male lower-pitched voices and male beard growth, might have arisen predominantly through intrasexual selection: that is, to serve the purpose of male–male competition instead of mate attraction. In this study, using a unique set of video stimuli, we measured people’s perceptions of the dominance and attractiveness of men who differ both in terms of voice pitch (4 levels from lower to higher pitched) and beard growth (4 levels from clean shaven to a month’s hair growth). We found a nonlinear relationship between lower pitch and increased attractiveness; men’s vocal attractiveness peaked at around 96 Hz. Beard growth had equivocal effects on attractiveness judgments. In contrast, perceptions of men’s dominance simply increased with increasing masculinity (i.e., with lower-pitched voices and greater beard growth). Together, these results suggest that the optimal level of physical masculinity might differ depending on whether the outcome is social dominance or mate attraction. These dual selection pressures might maintain some of the documented variability in male physical and behavioral masculinity that we see today. PMID:27004013
-
Kann, Laura; Olsen, Emily O'Malley; McManus, Tim; Harris, William A.; Shanklin, Shari L.; Flint, Katherine H.; Queen, Barbara; Lowry, Richard; Chyen, David; Whittle, Lisa; Thornton, Jemekia; Lim, Connie; Yamakawa, Yoshimi; Brener, Nancy; Zaza, Stephanie
2016-01-01
Problem: Sexual identity and sex of sexual contacts can both be used to identify sexual minority youth. Significant health disparities exist between sexual minority and nonsexual minority youth. However, not enough is known about health-related behaviors that contribute to negative health outcomes among sexual minority youth and how the prevalence…
-
Sexual dysfunction, depression, and the impact of antidepressants.
Kennedy, Sidney H; Rizvi, Sakina
2009-04-01
Sexual dysfunction is a common symptom of depression. Although decreased libido is most often reported, difficulties with arousal, resulting in vaginal dryness in women and erectile dysfunction in men, and absent or delayed orgasm are also prevalent. Sexual dysfunction is also a frequent adverse effect of treatment with most antidepressants and is one of the predominant reasons for premature drug discontinuation. Selective serotonin reuptake inhibitors are the most widely prescribed antidepressants and have significant effects on arousal and orgasm compared with antidepressants that target norepinephrine, dopamine, and melatonin systems. The availability of an antidepressant that does not cause or exacerbate sexual dysfunction represents an advance in pharmacotherapy for mood disorders and should reduce treatment noncompliance and decrease the need for switching antidepressants or adding antidotes. The purpose of this review was to provide an update on the prevalence, psychobiology, and relative adverse effect burden of sexual dysfunction associated with different antidepressants.
-
Lalor, Kevin; McElvaney, Rosaleen
2010-10-01
This paper reviews the literature on the nature and incidence of child sexual abuse, explores the link between child sexual abuse and later sexual exploitation, and reviews the literature on prevention strategies and effective interventions in child sexual abuse services. Our understanding of the international epidemiology of child sexual abuse is considerably greater than it was just 10 years ago, and studies from around the world are examined. Childhood sexual abuse can involve a wide number of psychological sequelae, including low self-esteem, anxiety, and depression. Numerous studies have noted that child sexual abuse victims are vulnerable to later sexual revictimization, as well as the link between child sexual abuse and later engagement in high-risk sexual behaviour. Survivors of child sexual abuse are more likely to have multiple sex partners, become pregnant as teenagers, and experience sexual assault as adults. Various models which attempt to account for this inter-relationship are presented; most invoke mediating variables such as low self-esteem, drug/alcohol use, PTSD and distorted sexual development. Prevention strategies for child sexual abuse are examined including media campaigns, school-based prevention programmes, and therapy with abusers. The results of a number of meta-analyses are examined. However, researchers have identified significant methodological limitations in the extant research literature that impede the making of recommendations for implementing existing therapeutic programmes unreservedly.
-
Directory of Open Access Journals (Sweden)
Vanessa Pirani Gaioso
2015-06-01
Full Text Available OBJECTIVE: to test a theoretical model based on the Parent-Based Expansion of the Theory of Planned Behavior examining relation between selected parental, teenager and cultural variables and Latino teenagers' intentions to engage in sexual behavior.METHOD: a cross-sectional correlational design based on a secondary data analysis of 130 Latino parent and teenager dyads.RESULTS: regression and path analysis procedures were used to test seven hypotheses and the results demonstrated partial support for the model. Parent familism and knowledge about sex were significantly associated with parents' attitudes toward sexual communication with their teenagers. Parent Latino acculturation was negatively associated with parents' self-efficacy toward sexual communication with their teenagers and positevely associated with parents' subjective norms toward sexual communication with their teenagers. Teenager knowledge about sex was significantly associated with higher levels of teenagers' attitudes and subjective norms about sexual communication with parents. Only the predictor of teenagers' attitudes toward having sex in the next 3 months was significantly associated with teenagers' intentions to have sex in the next 3 months.CONCLUSION: the results of this study provide important information to guide future research that can inform development of interventions to prevent risky teenager sexual behavior among Latinos.
-
Directory of Open Access Journals (Sweden)
Leif Edward Ottesen Kennair
2016-12-01
Full Text Available The current study sought to answer three key questions about explaining the emotion of regret in the domain of casual sex: Are sex differences in sexual regret robust or attenuated in a highly egalitarian culture? What proximate psychological variables might explain sex differences in sexual regret? And what accounts for within-sex variation in experiences of sexual regret about casual sex. We conducted a study of 263 Norwegian students (ages 19–37 who reported how much they regretted having either engaged in, or passed up, their most recent casual sexual experience. Sex differences in sexual regret are not attenuated in this sexually egalitarian culture. The study revealed sex differences in worries about pregnancy, STIs, and reputation; however, these predictors did not succeed in accounting for the sex differences in regret engaging in casual sex. Sexual gratification and socio-sexual orientation both predicted the sex differences in casual sex regret. In contrast, only socio-sexual orientation attenuated the sex difference in regret passing up casual sex. Predictors of within-sex variation in casual sexual regret included worry about sexual reputation, experienced gratification during the encounter, and socio-sexual orientation. Discussion focuses on implications for the psychological design features of this relatively neglected emotion.
-
Meston, Cindy; Trapnell, Paul
2005-01-01
This article presents data based on the responses of over 800 women who contributed to the development of the Sexual Satisfaction Scale for Women (SSS-W). The aim of this study was to develop a comprehensive, multifaceted, valid, and reliable self-report measure of women's sexual satisfaction and distress. Phase I involved the initial selection of items based on past literature and on interviews of women diagnosed with sexual dysfunction and an exploratory factor analysis. Phase II involved an additional administration of the questionnaire, factor analyses, and refinement of the questionnaire items. Phase III involved administration of the final questionnaire to a sample of women with clinically diagnosed sexual dysfunction and controls. Psychometric evaluation of the SSS-W conducted in a sample of women meeting DSM-IV-TR criteria for female sexual dysfunction and in a control sample provided preliminary evidence of reliability and validity. The ability of the SSS-W to discriminate between sexually functional and dysfunctional women was demonstrated for each of the SSS-W domain scores and total score. The SSS-W is a brief, 30-item measure of sexual satisfaction and sexual distress, composed of five domains supported by factor analyses: contentment, communication, compatibility, relational concern, and personal concern. It exhibits sound psychometric properties and has a demonstrated ability to discriminate between clinical and nonclinical samples.
-
Prior childhood sexual abuse in mothers of sexually abused children.
Oates, R K; Tebbutt, J; Swanston, H; Lynch, D L; O'Toole, B I
1998-11-01
To see if mothers who were sexually abused in their own childhood are at increased risk of their children being sexually abused and to see if prior sexual abuse in mothers affects their parenting abilities. Sixty-seven mothers whose children had been sexually abused by others and 65 control mothers were asked about sexual abuse in their own childhood. The sexually abused children of mothers who had been sexually abused in their own childhood were compared with the sexually abused children of mothers who had not suffered child sexual abuse as children. Comparisons were made on self-esteem, depression and behavior in the children. Thirty-four percent of mothers of sexually abused children gave a history of sexual abuse in their own childhoods, compared with 12% of control mothers. Assessment of the sexually abused children for self-esteem, depression and behavior at the time of diagnosis, after 18 months and after 5 years showed no difference in any of these measures at any of the three time intervals between those whose mothers had suffered child sexual abuse and those whose mothers had not been abused. In this study, sexual abuse in a mother's own childhood was related to an increased risk of sexual abuse occurring in the next generation, although prior maternal sexual abuse did not effect outcome in children who were sexually abused.
-
Textbook Sexual Inadequacy? A Review of Sexuality Texts.
Goettsch, Stephen L.
1987-01-01
Reviews eight current human sexuality textbooks for both their general organization and substantive content. Addresses specifically the content areas of sexual response cycle; sexual disfunction; acquaintance rape; AIDS and sexually transmitted diseases; extramarital sex; abortion; homosexuality; and pornography. Identifies as a recurring fault…
-
Sexual violence against female university students in Ethiopia.
Adinew, Yohannes Mehretie; Hagos, Mihiret Abreham
2017-07-24
Though many women are suffering the consequences of sexual violence, only few victims speak out as it is sensitive and prone to stigma. This lack of data made it difficult to get full picture of the problem and design proper interventions. Thus, the aim of this study was to assess the prevalence and factors associated with sexual violence among female students of Wolaita Sodo University, south Ethiopia. Institution based cross-sectional study was conducted among 462 regular female Wolaita Sodo University students on April 7/2015. Participants were selected by simple random sampling. Data were collected by self-administered questionnaire. Data entry and analysis was done by EPI info and SPSS statistical packages respectively. Descriptive statistics were done. Moreover, bivariate and multivariate analyses were also carried out to identify predictors of sexual violence. The age of respondents ranged from 18 to 26 years. Lifetime sexual violence was found to be 45.4%. However, 36.1% and 24.4% of respondents reported experiencing sexual violence since entering university and in the current academic year respectively. Life time sexual violence was positively associated with witnessing inter-parental violence as a child, rural childhood residence, having regular boyfriend, alcohol consumption and having friends who drink regularly; while it was negatively associated with discussing sexual issues with parents. Sexual violence is a common phenomenon among the students. More detailed research has to be conducted to develop prevention and intervention strategies.
-
Sexual Narcissism and the Perpetration of Sexual Aggression
Widman, Laura; McNulty, James K.
2009-01-01
Despite indirect evidence linking narcissism to sexual aggression, studies directly examining this relationship have yielded inconsistent results. Likely contributing to such inconsistencies, prior research has used global measures of narcissism not sensitive to whether the components of narcissism are activated in sexual versus non-sexual domains. The current research avoided such problems by using a measure of sexual narcissism to predict sexual aggression. In a sample of 299 men and women,...
-
Directory of Open Access Journals (Sweden)
McMahon Sharon
2004-08-01
Full Text Available Abstract Health Issue Much attention is devoted to women's reproductive health, but the formative and mature stages of women's sexual lives are often overlooked. We have analyzed cross-sectional data from the Sexual Behaviour module of the 2000/2001 Canadian Community Health Survey (CCHS, and reviewed the literature and available indicators of the sexual health of Canadian women. Key Findings Contemporary Canadian adolescents are becoming sexually active at younger ages than in previous generations. The gender gap between young males and females in age at first intercourse has virtually disappeared. The mean age at first intercourse for CCHS respondents aged 15–24 years was between 16 and 17. Canadian-born respondents are significantly younger at first intercourse than those who were born outside of Canada. Few adolescents recognize important risks to their sexual health. Older Canadians are sexually active, and continue to find emotional and physical satisfaction in their sexual relationships. Data Gaps and Recommendations Both health surveys and targeted research must employ a broader understanding of sexuality to measure changes in and determinants of the sexual health of Canadians. There is reluctance to direct questions about sexual issues to younger Canadians, even though increased knowledge of sexual health topics is associated with delayed onset of sexual intercourse. Among adults, sex-positive resources are needed to address aspects of aging, rather than medicalizing age-related sexual dysfunction. Age and gender-appropriate sexual health care, education, and knowledge are important not only for women of reproductive age, but for Canadians at all stages of life.
-
Integrating Neural Circuits Controlling Female Sexual Behavior.
Micevych, Paul E; Meisel, Robert L
2017-01-01
The hypothalamus is most often associated with innate behaviors such as is hunger, thirst and sex. While the expression of these behaviors important for survival of the individual or the species is nested within the hypothalamus, the desire (i.e., motivation) for them is centered within the mesolimbic reward circuitry. In this review, we will use female sexual behavior as a model to examine the interaction of these circuits. We will examine the evidence for a hypothalamic circuit that regulates consummatory aspects of reproductive behavior, i.e., lordosis behavior, a measure of sexual receptivity that involves estradiol membrane-initiated signaling in the arcuate nucleus (ARH), activating β-endorphin projections to the medial preoptic nucleus (MPN), which in turn modulate ventromedial hypothalamic nucleus (VMH) activity-the common output from the hypothalamus. Estradiol modulates not only a series of neuropeptides, transmitters and receptors but induces dendritic spines that are for estrogenic induction of lordosis behavior. Simultaneously, in the nucleus accumbens of the mesolimbic system, the mating experience produces long term changes in dopamine signaling and structure. Sexual experience sensitizes the response of nucleus accumbens neurons to dopamine signaling through the induction of a long lasting early immediate gene. While estrogen alone increases spines in the ARH, sexual experience increases dendritic spine density in the nucleus accumbens. These two circuits appear to converge onto the medial preoptic area where there is a reciprocal influence of motivational circuits on consummatory behavior and vice versa . While it has not been formally demonstrated in the human, such circuitry is generally highly conserved and thus, understanding the anatomy, neurochemistry and physiology can provide useful insight into the motivation for sexual behavior and other innate behaviors in humans.
-
Integrating Neural Circuits Controlling Female Sexual Behavior
Directory of Open Access Journals (Sweden)
Paul E. Micevych
2017-06-01
Full Text Available The hypothalamus is most often associated with innate behaviors such as is hunger, thirst and sex. While the expression of these behaviors important for survival of the individual or the species is nested within the hypothalamus, the desire (i.e., motivation for them is centered within the mesolimbic reward circuitry. In this review, we will use female sexual behavior as a model to examine the interaction of these circuits. We will examine the evidence for a hypothalamic circuit that regulates consummatory aspects of reproductive behavior, i.e., lordosis behavior, a measure of sexual receptivity that involves estradiol membrane-initiated signaling in the arcuate nucleus (ARH, activating β-endorphin projections to the medial preoptic nucleus (MPN, which in turn modulate ventromedial hypothalamic nucleus (VMH activity—the common output from the hypothalamus. Estradiol modulates not only a series of neuropeptides, transmitters and receptors but induces dendritic spines that are for estrogenic induction of lordosis behavior. Simultaneously, in the nucleus accumbens of the mesolimbic system, the mating experience produces long term changes in dopamine signaling and structure. Sexual experience sensitizes the response of nucleus accumbens neurons to dopamine signaling through the induction of a long lasting early immediate gene. While estrogen alone increases spines in the ARH, sexual experience increases dendritic spine density in the nucleus accumbens. These two circuits appear to converge onto the medial preoptic area where there is a reciprocal influence of motivational circuits on consummatory behavior and vice versa. While it has not been formally demonstrated in the human, such circuitry is generally highly conserved and thus, understanding the anatomy, neurochemistry and physiology can provide useful insight into the motivation for sexual behavior and other innate behaviors in humans.
-
Correlates of sexual initiation among European adolescents
Carli, Vladimir; Hadlaczky, Gergö; Sarchiapone, Marco; Apter, Alan; Balazs, Judit; Banzer, Raphaela; Bobes, Julio; Brunner, Romuald; Cosman, Doina; Farkas, Luca; Haring, Christian; Hoven, Christina W.; Kaess, Michael; Kahn, Jean Pierre; McMahon, Elaine; Postuvan, Vita; Sisask, Merike; Värnik, Airi; Zadravec Sedivy, Nusa; Wasserman, Danuta
2018-01-01
Background Sexuality is a physiological component of adolescent development, though early initiation is associated with reproductive health risk. This study aimed at identifying correlates and predictors of sexual initiation in a large multinational cohort of European adolescents. Methods A questionnaire addressing socio-demographics, behaviours, mental health and sexual activity, was delivered to 11,110 adolescents recruited from 168 randomly selected schools in 10 European countries between 2009 and 2011. A follow-up questionnaire was delivered after 12 months. The longitudinal association of baseline risk behaviors, psychological attributes and contextual vulnerabilities, with sexual initiation during follow-up was evaluated through simple and multivariable age/sex stratified logistic regression. Multinomial logistic regression measured the association between predictors and sexual initiation with or without coexisting reproductive risk factors, such as multiple partners or infrequent condom use. Results Baseline sexual experience was reported by 19.2% of 10,757 respondents (median age 15; IQR 14–15; females 59.6%). This was significantly more frequent among pupils older than 15 (41%) and males (20.8%). Of 7,111 pupils without previous experience who were available at follow-up (response rate 81.8%), 17% reported sexual initiation, without differences between females and males. Baseline smoking (age/sex adjusted odds ratio [aOR] 3.63), alcohol use (aOR 2.95), illegal drugs use (aOR 2.72), and poor sleep (aOR 1.71) predicted sexual initiation. Stratified analyses showed a particularly strong association in case of younger and female pupils, and, among girls, when initiation was reported together with multiple partners and/or infrequent condom use. Externalizing (i.e. conduct and hyperactivity) symptoms independently predicted sexual initiation. Internalizing difficulties (i.e. emotional and peer problems) were negatively associated with early and risky sexual
-
Kaur, Tejbeer; Zamani, Darius; Tong, Ling; Rubel, Edwin W; Ohlemiller, Kevin K; Hirose, Keiko; Warchol, Mark E
2015-11-11
Macrophages are recruited into the cochlea in response to injury caused by acoustic trauma or ototoxicity, but the nature of the interaction between macrophages and the sensory structures of the inner ear remains unclear. The present study examined the role of fractalkine signaling in regulating the injury-evoked behavior of macrophages following the selective ablation of cochlear hair cells. We used a novel transgenic mouse model in which the human diphtheria toxin receptor (huDTR) is selectively expressed under the control of Pou4f3, a hair cell-specific transcription factor. Administration of diphtheria toxin (DT) to these mice resulted in nearly complete ablation of cochlear hair cells, with no evident pathology among supporting cells, spiral ganglion neurons, or cells of the cochlear lateral wall. Hair cell death led to an increase in macrophages associated with the sensory epithelium of the cochlea. Their numbers peaked at 14 days after DT and then declined at later survival times. Increased macrophages were also observed within the spiral ganglion, but their numbers remained elevated for (at least) 56 d after DT. To investigate the role of fractalkine signaling in macrophage recruitment, we crossed huDTR mice to a mouse line that lacks expression of the fractalkine receptor (CX3CR1). Disruption of fractalkine signaling reduced macrophage recruitment into both the sensory epithelium and spiral ganglion and also resulted in diminished survival of spiral ganglion neurons after hair cell death. Our results suggest a fractalkine-mediated interaction between macrophages and the neurons of the cochlea. It is known that damage to the inner ear leads to recruitment of inflammatory cells (macrophages), but the chemical signals that initiate this recruitment and the functions of macrophages in the damaged ear are unclear. Here we show that fractalkine signaling regulates macrophage recruitment into the cochlea and also promotes the survival of cochlear afferents after
-
‘Not My Child’: Parents’ Denial About Adolescent Sexuality in Harare, Zimbabwe
Directory of Open Access Journals (Sweden)
Manase Kudzai Chiweshe
2018-03-01
Full Text Available Objective: To find out adult views on adolescent sexualities in Zimbabwe and how adults construct sexual cultures that deny adolescence access to sex.Materials and methods: The paper uses qualitative methodologies, with purposively selected parents and key informants. A total of ten in depth interviews, four focus groups and six key informant interviews with purposively sampled male and female respondents were conducted. Key informants included a headmaster, teacher, social worker, nurses and a member of traditional healers association.Results: Parents that were interviewed denied that their adolescent children were sexually active. This denial of adolescent sexuality was seen throughout the interviews. The denial of adolescent sexuality was linked to the other themes that emerged including sexual surveillance and sexual communication, school pregnancy, STIs and sexual education, and adult anxiety on adolescent sex.Conclusion: The denial of youth sexuality has serious impacts on youths’ access to information and ability to protect themselves from sexually transmitted diseases and HIV. We argue that government policies and lack of comprehensive sex education in schools are based on this denial of adolescent sexuality and should be addressed.
-
Sexual Orientation as Interpretation? Sexual Desires, Concepts, and Choice
Directory of Open Access Journals (Sweden)
Díaz-León E.
2017-07-01
Full Text Available Are sexual orientations freely chosen? The idea that someone’s sexual orientation is not a choice is very influential in the mainstream LGBT political movement. But do we have good reasons to believe it is not a choice? Going against the orthodoxy, William Wilkerson has recently argued that sexual orientation is partly constituted by our interpretations of our own sexual desires, and we choose these interpretations, so sexual orientation is partly constituted by choice. In this paper I aim to examine the question of whether our interpretations of our own sexual desires are constitutive of our sexual orientations. I will argue that whereas Wilkerson’s argument for the claim that sexual orientations are in part constituted by our chosen interpretations of our sexual desires is not sound, there are good reasons for endorsing a weaker claim, namely, that there are different but equally apt descriptions of the same sexual desires, depending on which concepts we have.
-
Advances in pharmacotherapy for treating female sexual dysfunction.
Nappi, Rossella E; Cucinella, Laura
2015-04-01
'Female sexual dysfunction' (FSD) is an umbrella term comprising a range of common disorders, including hypoactive sexual desire, reduced subjective and/or physical genital arousal (poor sensation, vasocongestion, lubrication), sexual pain and inability to achieve orgasm/satisfaction, which are multidimensional by nature and often coexisting. Psychological and contextual factors have a significant influence on organic components of sexual response and behavior and a tailored medical approach to sexual symptoms is inevitably limited. The paper reports the most recent advances in pharmacotherapy for women taking into account the biopsychosocial model. Hormone therapy, including estrogens, testosterone, tibolone and dehydroepiandrosterone, are discussed in term of efficacy and safety in postmenopausal women both for female sexual interest/arousal disorder (FSIAD) and genito-pelvic pain/penetration disorder. Ospemifene, a selective estrogen receptor modulator, approved to treat dyspareunia at menopause, is also discussed. Data on psychoactive agents for treatment of FSIAD in premenopausal women are discussed, including the potential use of on-demand combined hormonal (testosterone) and non-hormonal (buspirone or sildenafil) treatments to address possible neurophysiological profiles of women. We are still waiting for an approved pharmacotherapy for FSD. This is not the result of gender inequality in sexual medicine, but it reflects the need of balancing benefits and risks in order to provide effective and safe treatments to women of any age.
-
Gendered Sexuality : Exploring dynamics of the sexual double standard
Emmerink, P.M.J.|info:eu-repo/dai/nl/363312633
2017-01-01
The sexual double standard (SDS) is a divergent set of expectations for boys and men, and girls and women for engaging in romantic and sexual behaviour. It prescribes that boys and men should be sexually active, assertive and take sexual initiative, whereas girls and women should be sexually
-
Orchid pollination by sexual deception: pollinator perspectives.
Gaskett, A C
2011-02-01
becoming well understood for some species, but visual and tactile signals such as colour, shape, and texture remain neglected. Experimental manipulations that test for function, multi-signal interactions, and pollinator perception of these signals are required. Furthermore, other forms of deception such as exploitation of pollinator sensory biases or mating preferences merit more comprehensive investigation. Application of molecular techniques adapted from model plants and animals is likely to deliver new insights into orchid signalling, and pollinator perception and behaviour. There is little current evidence that sexual deception drives any species-level selection on pollinators. Pollinators do learn to avoid deceptive orchids and their locations, but this is not necessarily a response specific to orchids. Even in systems where evidence suggests that orchids do interfere with pollinator mating opportunities, considerable further research is required to determine whether this is sufficient to impose selection on pollinators or generate antagonistic coevolution or an arms race between orchids and their pollinators. Botanists, taxonomists and chemical ecologists have made remarkable progress in the study of deceptive orchid pollination. Further complementary investigations from entomology and behavioural ecology perspectives should prove fascinating and engender a more complete understanding of the evolution and maintenance of such enigmatic plant-animal interactions. © 2010 The Author. Biological Reviews © 2010 Cambridge Philosophical Society.
-
Family Violence & Sexual Assault Bulletin, 1996.
Geffner, Robert, Ed.
These two Bulletins contain selected articles that highlight research and treatment issues in child abuse and child sexual abuse. The first issue includes the following featured articles: (1) "The Relationships between Animal Abuse and Other Forms of Family Violence" (Phil Arkow), which addresses animal cruelty as a harbinger of…
-
Maniglio, Roberto
2015-07-01
To elucidate the significance, nature, and direction of the potential relationship between child sexual abuse and conduct disorder, all the pertinent studies were reviewed. Ten databases were searched. Blind assessments of study eligibility and quality were performed by two independent researchers. Thirty-six studies including 185,358 participants and meeting minimum quality criteria that were enough to ensure objectivity and to not invalidate results were analyzed. Across the majority of studies, conduct disorder was significantly and directly related to child sexual abuse, especially repeated sexual molestation and abuse involving penetration, even after controlling for various sociodemographic, family, and clinical variables. The association between child sexual abuse and conduct disorder was not confounded by other risk factors, such as gender, socioeconomic status, school achievement, substance problems, physical abuse, parental antisocial behavior or substance problems, parent-child relationships, and family disruption, conflict, or violence. Evidence for a significant interactive effect between child sexual abuse and monoamine oxidase A gene on conduct disorder was scant. Early sexual abuse might predispose to the subsequent onset of conduct disorder which, in turn, may lead to further sexual victimization through association with sexually abusive peers or involvement in dangerous situations or sexual survival strategies. © The Author(s) 2014.
-
Postmating sexual conflict and female control over fertilization during gamete interaction.
Firman, Renée C
2018-06-01
Males and females rarely have identical evolutionary interests over reproduction, and when the fitness of both sexes is dependent upon paternity outcomes, sexual conflict over fertilization is inevitable. In internal fertilizers, the female tract is a formidable selective force on the number and integrity of sperm that reach the egg. Selection on sperm quality is intensified when females mate multiply and rival males are forced to compete for fertilizations. While male adaptations to sperm competition have been well documented (e.g., increased sperm fertilizing capacity), much less attention has been given to the evolutionary consequences of postmating sexual conflict for egg form and function. Specifically, increased sperm competitiveness can be detrimental by giving rise to an elevation in reproductive failure resulting from polyspermy. Spanning literature on both internal and external fertilizers, in this review I discuss how females respond to sperm competition via fertilization barriers that mediate sperm entry. These findings, which align directly with sexual conflict theory, indicate that females have greater control over fertilization than has previously been appreciated. I then consider the implications of gametic sexual conflict in relation to the development of reproductive isolation and speculate on potential mechanisms accounting for "egg defensiveness." Finally, I discuss the functional significance of egg defensiveness for both the sexes, and sperm selection for females. © 2018 New York Academy of Sciences.
-
Risky Sexual Behaviours among Adolescents in Owerri Municipal ...
African Journals Online (AJOL)
Erah
2009-03-01
Mar 1, 2009 ... exist between adolescents RSBs and age at first sexual experience or adolescent perception of parental ... of unwanted pregnancy, abortion or contracting and ... in India and ... mixed), from where the random selection.
-
Effects of a sexual rehabilitation intervention program on stroke patients and their spouses.
Song, HoSook; Oh, HyunSoo; Kim, HwaSoon; Seo, WhaSook
2011-01-01
The present study was conducted to examine whether a sexual rehabilitation intervention program, which was developed during the present study and designed for stroke patients and their spouses, was effective in terms of sexual knowledge and satisfaction and frequency of sexual activity at 1 month after intervention. The study subjects were conveniently selected from stroke patients admitted to the neurology department at a university hospital located in Incheon, South Korea. A total of 46 subjects (12 couples for the experimental group and 11 couples for the control group) were included. Sexual knowledge, sexual satisfaction, frequency of sexual activity, level of cognitive function, and performance with respect to daily living activities were measured. The results obtained demonstrated that the devised sexual rehabilitation intervention program significantly increased sexual satisfaction and frequency of sexual activity, but that it did not promote sexual knowledge. The present study has meaning because the intervention program could be used as a practical guideline for post-stroke sexual rehabilitation. In addition, the findings of this study provide evidence regarding the usefulness of sexual education and counseling on the sexual health of post-stroke patients and their spouses.
-
Foellmer, Matthias W; Fairbairn, Daphne J
2005-02-01
Mate search plays a central role in hypotheses for the adaptive significance of extreme female-biased sexual size dimorphism (SSD) in animals. Spiders (Araneae) are the only free-living terrestrial taxon where extreme SSD is common. The "gravity hypothesis" states that small body size in males is favoured during mate search in species where males have to climb to reach females, because body length is inversely proportional to achievable speed on vertical structures. However, locomotive performance of males may also depend on relative leg length. Here we examine selection on male body size and leg length during mate search in the highly dimorphic orb-weaving spider Argiope aurantia, using a multivariate approach to distinguish selection targeted at different components of size. Further, we investigate the scaling relationships between male size and energy reserves, and the differential loss of reserves. Adult males do not feed while roving, and a size-dependent differential energy storage capacity may thus affect male performance during mate search. Contrary to predictions, large body size was favoured in one of two populations, and this was due to selection for longer legs. Male size was not under selection in the second population, but we detected direct selection for longer third legs. Males lost energy reserves during mate search, but this was independent of male size and storage capacity scaled isometrically with size. Thus, mate search is unlikely to lead to selection for small male size, but the hypothesis that relatively longer legs in male spiders reflect a search-adapted morphology is supported.
-
Coates, Peter S.; Brussee, Brianne E.; Ricca, Mark A.; Dudko, Jonathan E.; Prochazka, Brian G.; Espinosa, Shawn P.; Casazza, Michael L.; Delehanty, David J.
2017-08-10
Greater sage-grouse (Centrocercus urophasianus; hereinafter, "sage-grouse") are highly dependent on sagebrush (Artemisia spp.) dominated vegetation communities for food and cover from predators. Although this species requires the presence of sagebrush shrubs in the overstory, it also inhabits a broad geographic distribution with significant gradients in precipitation and temperature that drive variation in sagebrush ecosystem structure and concomitant shrub understory conditions. Variability in understory conditions across the species’ range may be responsible for the sometimes contradictory findings in the scientific literature describing sage-grouse habitat use and selection during important life history stages, such as nesting. To help understand the importance of this variability and to help guide management actions, we evaluated the nesting and brood-rearing microhabitat factors that influence selection and survival patterns in the Great Basin using a large dataset of microhabitat characteristics from study areas spanning northern Nevada and a portion of northeastern California from 2009 to 2016. The spatial and temporal coverage of the dataset provided a powerful opportunity to evaluate microhabitat factors important to sage-grouse reproduction, while also considering habitat variation associated with different climatic conditions and areas affected by wildfire. The summary statistics for numerous microhabitat factors, and the strength of their association with sage-grouse habitat selection and survival, are provided in this report to support decisions by land managers, policy-makers, and others with the best-available science in a timely manner.
-
Mediators of Sexual Revictimization Risk in Adult Sexual Assault Victims
Ullman, Sarah E.; Vasquez, Amanda L.
2015-01-01
This study examined sexual risk behaviors and sexual refusal assertiveness in relationship to child sexual abuse (CSA), emotion dysregulation, and adult sexual revictimization. Path analyses of 1,094 survivors who had sex in the past year were done to examine sexual risk behavior, and sexual refusal assertiveness mediational pathways by which CSA severity and emotion dysregulation may affect revictimization over one year in adult female sexual assault survivors. Exchanging sex for money and sexual refusal assertiveness were significantly associated with emotion dysregulation, whereas exchanging sex for money, and not sexual refusal assertiveness, was only significantly related to CSA severity. Both exchanging sex for money and sex refusal assertiveness mediated the relationship between emotion dysregulation and adult sexual revictimization. Exchanging sex for money mediated the CSA severity-revictimization relationship. These findings demonstrate the importance of considering both risky and protective sexual behaviors in research and prevention programming that address sexual revictimization in women. PMID:25942287
-
Johns, A; Gotoh, H; McCullough, E L; Emlen, D J; Lavine, L C
2014-10-01
The exaggerated weapons and ornaments of sexual selection are condition-dependent traits that often grow to exaggerated proportions. The horns of male rhinoceros beetles are extremely sensitive to the larval nutritional environment and are used by rival males in combat over access to females. In contrast to horns, other parts of the body, such as wings, eyes, and legs, scale proportionally with body size, whereas others, such as males' external genitalia, are invariant with body size, regardless of nutrition. We document how body parts of the Asian rhinoceros beetle, Trypoxylus dichotomus, exhibit plasticity and constraint in response to nutritional condition. We discuss the implications of these results for the evolution of condition-dependent and condition-independent traits in animals. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.
-
A review of affecting factors on sexual satisfaction in women.
Shahhosseini, Zohreh; Gardeshi, Zeinab Hamzeh; Pourasghar, Mehdi; Salehi, Fariba
2014-12-01
Sex is a complex, important and sensitive issue in human being and interwoven with the whole of human existence. Given the serious changes in attitude, function and behavior in sex, the need to address sexual function, especially sexual satisfaction, is felt completely. Sexual satisfaction has a very important role in creating marital satisfaction and any defect in sexual satisfaction is significantly associated with risky sexual behaviors, serious mental illness, social crimes and ultimately divorce. The aim of this study was to explore affecting factors on sexual satisfaction in women based on an overview in scientific database. In this narrative review the researchers searched MEDLINE database, Google Scholar and Science Direct as well as Persian database like Scientific Information Database with search terms of sexual satisfaction and sexual function, restricted to English/ Persian language, during the 20 years ago. Then those articles written by renowned experts were selected. In this regard, 57 articles have been reviewed, which 30 articles related to this research have been extracted. The findings were divided in to four categories including: Demographic factors, Pathophysiological factors, Psychological factors and Sociocultural factors. Sexuality, especially sexual intimacy is sophisticated and yet elegant affair that the other persons has different definitions and different functions. Discrepancies in the results of the studies show that analysis of factors affecting sexual satisfaction regardless of the women's' sociocultural context, religious beliefs, and personal attitudes is undoubtedly inefficient, unscientific and irrational.
-
Zauner, Hans; Begemann, Gerrit; Marí-Beffa, Manuel; Meyer, Axel
2003-01-01
The possession of a conspicuous extension of colored ventral rays of the caudal fin in male fish of swordtails (genus Xiphophorus) is a prominent example for a trait that evolved by sexual selection. To understand the evolutionary history of this so-called sword molecularly, it is of interest to unravel the developmental pathways responsible for extended growth of sword rays during development of swordtail males. We isolated two msx genes and showed that they are differentially regulated during sword outgrowth. During sword growth in juvenile males, as well as during testosterone-induced sword development and fin ray regeneration in the sword after amputation, expression of msxC is markedly up-regulated in the sword forming fin rays. In contrast, msxE/1 is not differentially expressed in ventral and dorsal male fin rays, suggesting a link between the development of male secondary sexual characters in fins and up-regulation of msxC expression. In addition, we showed that msx gene expression patterns differ significantly between Xiphophorus and zebrafish. We also included in our study the gonopodium, a testosterone-dependent anal fin modification that serves as a fertilization organ in males of live-bearing fishes. Our finding that increased levels of msxC expression are associated with the testosterone-induced outgrowth of the gonopodium might suggest either that at least parts of the signaling pathways that pattern the evolutionary older gonopodium have been coopted to evolve a sexually selected innovation such as the sword or that increased msxC expression may be inherent to the growth process of long fin rays in general.
-
Sexual practices among western Kenyan youth
Directory of Open Access Journals (Sweden)
AA Egal
2011-01-01
Full Text Available Universally the importance of proper sex behaviors and development amongst youngsters is well recognized and documented. Nations and communities are committed to detecting early sexual misbehaviors, amongst others in growing children, in order to foster sound societies. Concomitantly, some of the so-called “remote areas”, which are far from the political centers, seem to have less attention from the national resources. In practice, most of the social problems are detected in these “remote areas”. In this context, a survey questionnaire was conducted among 217 randomly selected school-age children in 15 sub-locations in Kisamu, in western Kenya. The main goals were to create awareness among school-going children regarding safe sex and sexually transmitted diseases and to explore the existing sexual behaviors in the research area. Statistical analysis on the research question revealed that primary school children begin their first sexual activity at as early as six years while older secondary school pupils start at around the age of eight and half. Out-ofschool children indicated that they started their first sexual activities at the age of 10. Similarly, when asked about the frequency of sexual engagement in the year before, the frequency was higher among schoolchildren than those out of school. These findings raised a serious fundamental question on the effectiveness of the existing child protection policies in schools in the research areas. Therefore, all stakeholders should review school protection mechanisms where special care could be given to primary schools, where the impact is most serious.
-
Prevalence of childhood sexual abuse among Mexican adolescents.
Pineda-Lucatero, A G; Trujillo-Hernández, B; Millán-Guerrero, R O; Vásquez, C
2009-03-01
To determine the characteristics and prevalence of previous child sexual abuse among a group of Mexican junior high school students. A total of 1067 adolescents of both genders were selected to fill out a survey about child sexual abuse. The prevalence of child sexual abuse was 18.7% (n = 200). It was more frequent in girls (58%) than in boys (42%). Sexual abuse involved physical contact in 75% of those cases reporting abuse. The aggressors were neighbours (50.3%), relatives (36.8%) and strangers (13.9%). Abuse was committed through deception in 90% of the cases and involved physical mistreatment in 10% of the cases. Of the victims, 14.4% had spoken about the problem and 3.7% had taken legal action. And 9.6% of those surveyed stated that they required psychological counselling. In the population studied, the prevalency of child sexual abuse was greater than that reported in Mexico City (4.3-8.4%), although it was similar to that found in the Spanish child population (15-23%). The risk of sexual abuse is greater for girls and the principal aggressors are male neighbours, family friends and relatives; the abuse is committed in the home of the aggressor or the victim and very few cases are reported to the authorities.
-
On cultural transformations of sexuality and gender in recent decades
Directory of Open Access Journals (Sweden)
Sigusch, Volkmar
2004-10-01
Full Text Available Western cultures have witnessed a tremendous cultural and social transformation of sexuality in the years since the sexual revolution. Apart from a few public debates and scandals, the process has moved along gradually and quietly. Yet its real and symbolic effects are probably much more consequential than those generated by the sexual revolution of the sixties. Sigusch refers to the broad-based recoding and reassessment of the sexual sphere during the eighties and nineties as the "neosexual revolution". The neosexual revolution is dismantling the old patterns of sexuality and reassembling them anew. In the process, dimensions, intimate relationships, preferences and sexual fragments emerge, many of which had submerged, were unnamed or simply did not exist before. In general, sexuality has lost much of its symbolic meaning as a cultural phenomenon. Sexuality is no longer the great metaphor for pleasure and happiness, nor is it so greatly overestimated as it was during the sexual revolution. It is now widely taken for granted, much like egotism or motility. Whereas sex was once mystified in a positive sense - as ecstasy and transgression, it has now taken on a negative mystification characterized by abuse, violence and deadly infection. While the old sexuality was based primarily upon sexual instinct, orgasm and the heterosexual couple, neosexualities revolve predominantly around gender difference, thrills, self-gratification and prosthetic substitution. From the vast number of interrelated processes from which neosexualities emerge, three empirically observable phenomena have been selected for discussion here: the dissociation of the sexual sphere, the dispersion of sexual fragments and the diversification of intimate relationships. The outcome of the neosexual revolution may be described as "lean sexuality" and "self-sex".
-
On cultural transformations of sexuality and gender in recent decades.
Sigusch, Volkmar
2004-10-20
Western cultures have witnessed a tremendous cultural and social transformation of sexuality in the years since the sexual revolution. Apart from a few public debates and scandals, the process has moved along gradually and quietly. Yet its real and symbolic effects are probably much more consequential than those generated by the sexual revolution of the sixties. Sigusch refers to the broad-based recoding and reassessment of the sexual sphere during the eighties and nineties as the "neosexual revolution". The neosexual revolution is dismantling the old patterns of sexuality and reassembling them anew. In the process, dimensions, intimate relationships, preferences and sexual fragments emerge, many of which had submerged, were unnamed or simply did not exist before. In general, sexuality has lost much of its symbolic meaning as a cultural phenomenon. Sexuality is no longer the great metaphor for pleasure and happiness, nor is it so greatly overestimated as it was during the sexual revolution. It is now widely taken for granted, much like egotism or motility. Whereas sex was once mystified in a positive sense - as ecstasy and transgression, it has now taken on a negative mystification characterized by abuse, violence and deadly infection. While the old sexuality was based primarily upon sexual instinct, orgasm and the heterosexual couple, neosexualities revolve predominantly around gender difference, thrills, self-gratification and prosthetic substitution. From the vast number of interrelated processes from which neosexualities emerge, three empirically observable phenomena have been selected for discussion here: the dissociation of the sexual sphere, the dispersion of sexual fragments and the diversification of intimate relationships. The outcome of the neosexual revolution may be described as "lean sexuality" and "self-sex".
-
Teen pregnancy, motherhood, and unprotected sexual activity.
Koniak-Griffin, Deborah; Lesser, Janna; Uman, Gwen; Nyamathi, Adeline
2003-02-01
The sexual behaviors and attitudes toward condom use of adolescent mothers (N = 572) from ethnic minority groups were examined. Constructs from social cognitive theory (SCT), the theory of reasoned action (TRA), and the theory of planned behavior (TPB; e.g., intentions to use condoms, self-efficacy, outcome expectancies) were measured with questionnaires. Measures of AIDS and condom-use knowledge and selected psychosocial, behavioral, and demographic variables were included. Many adolescents reported early onset of sexual activity, multiple lifetime sexual partners, substance use, and childhood sexual or physical abuse. Only 18% stated a condom was used at last intercourse. Using hierarchical regression analysis, 13% of the variance for factors associated with unprotected sex was accounted for by TRA constructs. Other variables contributed an additional 17% of the variance. Unprotected sex was associated with behavioral intentions to use condoms, pregnancy, having a steady partner, more frequent church service attendance, and ever having anal sex. Findings support the urgent need for broad-based HIV prevention efforts for adolescent mothers that build on theoretical concepts and address the realities of their lives. Copyright 2003 Wiley Periodicals, Inc.
-
Reissing, Elke D; Binik, Yitzchak M; Khalifé, Samir; Cohen, Deborah; Amsel, Rhonda
2003-01-01
This study investigated the role of sexual and physical abuse, sexual self-schema, sexual functioning, sexual knowledge, relationship adjustment, and psychological distress in 87 women matched on age, relationship status, and parity and assigned to 3 groups--vaginismus, dyspareunia/vulvar vestibulitis syndrome (VVS), and no pain. More women with vaginismus reported a history of childhood sexual interference, and women in both the vaginismus and VVS groups reported lower levels of sexual functioning and a less positive sexual self-schema. Lack of support for traditionally held hypotheses concerning etiological correlates of vaginismus and the relationship between vaginismus and dyspareunia are discussed.
-
Think globally, act locally: understanding sexual harassment from a cross-cultural perspective.
Ulusoy, Hatice; Swigart, Valerie; Erdemir, Firdevs
2011-06-01
Sexual harassment in medical education has been studied in the Americas, Europe and Asia; however, little is known about sexual harassment in Middle Eastern cultures. Our initial aim was to describe the sexual harassment of female doctors-in-training by male patients and their relatives in Turkey. During our analysis of data, we expanded our objectives to include the formulation of a framework that can provide a theoretical background to enhance medical educators' understanding of sexual harassment across cultures. Questionnaires were provided to female resident doctors. Respondents were asked about their experiences of sexual harassment, about their reactions and about any precautionary measures they had used. Descriptive statistics were generated using SPSS software. Qualitative data were analysed using content analysis. Forty-nine (51.0%) of 96 distributed questionnaires were completed. Thirty-three (67.3%) participants stated that they had been sexually harassed by a patient or patient's relative at some point in their career. 'Gazing at the doctor in a lewd manner', selected by 25 (51.0%) participants, was the most common form of harassment. The methods of coping selected by the highest numbers of respondents involved seeking the discharge of the patient (24.2%), avoiding contact with the patient or relatives (24.2%) and showing rejection (21.2%). Participants' comments about the prevention of sexual harassment revealed a deep sense of need for protection. The interface between quantitative and qualitative findings and a review of the literature supported the development of a value-based, cross-cultural conceptual framework linking the valuing of hierarchy and conservatism with the occurrence of sexual harassment. We relate our findings to issues of patriarchy, power and socio-cultural influences that impact both the perpetrator and the target of sexual harassment. Medical educators are responsible for the control and prevention of sexual harassment of
-
Sexual Fears and Avoidant Sexual Behavior in Medical Students.
Popov, Stefan P; Mateva, Nonka G; Iliev, Yanko T; Dechev, Ivan D; Karalilova, Rositsa V
2015-01-01
Sexual fears, sometimes in the form of phobias, lead to aversive or sexually avoidant behavior blocking sexual closeness and resulting in deep personal and interpersonal distress. To determine the types of sexual fears and aversive behavior in young people of reproductive age (students) and their degree of markedness as to encourage a further implementation of prevention programs and interventions. The study included 116 fifth-year medical students in Plovdiv Medical University. Of these, 55 men and 61 women were assessed with the Sexual Aversion Scale, a 30-item self-rating questionnaire. The Diagnostic and Statistical Manual of Mental Disorders criteria of sexual aversion were used. The statistical analyses used were descriptive statistics and independent samples t-test. Sexual fears and aversive or blocking behavior are mild to moderate, mean score of 1.54 ± 0.04, without statistically significant gender differences. Both sexes have established fear-related sexual aversive motives of sexual behavior related to the risk of unwanted pregnancy and HIV infection. Women have significantly higher average scores for the following statements: fear of sexual intercourse (1.61 vs 1.25), avoidance of situations in which they may be involved sexually (1.95 vs 1.51), avoidance of genital sexual contact (1.44 vs 1.16), fear of catching a sexually transmitted disease (2.46 vs 2.09 ), fear of pregnancy (2.61 vs 2.15) and concerns what other people think of them (2.34 vs 1.93 ). Sexual fears and aversive or blocking behavior were mild to moderate. In both sexes similar fears--aversive or blocking patterns of sexual behavior were found, mainly associated with the fear of unwanted pregnancy and the risk of HIV infection, more expressed in women.
-
ORIGINAL ARTICLE Sexual and Reproductive Health Services Use ...
African Journals Online (AJOL)
2018-01-01
Jan 1, 2018 ... sexually active, father-child communication, religion and place of residence were significantly ... workers, school teachers, parents, in schools boys and girls and selected ..... Transformation of the Future.Youth in Sub- saharan ...
-
The experience of First Sexual Intercourse: an Exploratory Study in Greek Women
Directory of Open Access Journals (Sweden)
Martha Moraitou
2011-01-01
Full Text Available Background: A young person's first sexual intercourse is often a remarkable and memorable experience.However, little information exists regarding contextual factors of this first experience and the possible effects ontheir subsequent sexual lifeObjective: This study explored the conditions of and women’s emotional reactions to first sexual intercourse(FSI, as well as FSI’s impact on their future sexual experiences.Methodology: Participants were 899 women aged 19 to 40 yrs, registered in 23 arbitrarily selected GPs privatepractices. They completed a 30-item questionnaire regarding their first sexual intercourse experience.Results: It was found that information sources for sexual issues (family vs media significantly influence both theadoption of responsible sexual behaviours and the formation of feelings preceding sexual initiation (p<0.05. Thestudy also demonstrated that even when FSI is perceived as voluntary other correlates (e.g. woman’s and /orpartner’s age, contraceptive use etc. affect women’s emotional reaction to first coital experience and theirresponse to future sexual encounters.Conclusions: The findings of this study provide initial data to suggest that the first sexual intercourse experiencesignificantly impacts women’s sexual life. Health professionals should be aware of this information in thedevelopment of programs focusing on the promotion of sexual health for adolescents or parents; education.
-
Effects of Sexuality Information on Sexual Behavior and Control of ...
African Journals Online (AJOL)
There was significant correlation between knowledge of sexuality and sexual ... Conclusion: It is recommended that instructors on sexuality education be ... youths facts of sexuality, contraception and sexually transmitted diseases to reduce the ...
-
Comparison of Sexual Problems in Fertile and Infertile Couples
Directory of Open Access Journals (Sweden)
Zahra Zare
2017-09-01
Full Text Available Introduction: Infertility is known to have a negative effect on couple's life and in most cases it has a profound impact on sexual relations. Sexual problems may be the cause of infertility or may arise as a result of infertility. The aim of this study was to compare the sexual problems in fertile and infertile couples. Methods: This cross-sectional study was performed on 110 infertile and 110 fertile couples referring to Montaserieh infertility center and five health centers in Mashhad which were selected as class clustering method and easy method. Data collection tools included demographic questionnaires and Golombok-Rust Inventory. The collected information was analyzed by SPSS software and descriptive and inferential statistics. Results: No significant difference was found between fertile 26 (17, 37 and infertile 26(18, 37 women in terms of total score of sexual problems and other aspects of sexual problems (except infrequency. The women in the fertile group had higher infrequency than infertile women. Total score of sexual problems in fertile men was 18.5 (13, 27 and in infertile men 25 (19, 31 and the difference was statistically significant. Infertile men reported more problems in no relation, impotency and premature ejaculation compared to fertile men. Men in both fertile and infertile group reported more sexual problems than women. Conclusion: In view of the more frequent sexual problems in infertile men than infertile women, it seems that it is necessary to pay more attention to sexual aspects of infertility in men and design the training programs for sexual and marital skills in infertility centers.
-
Integration of sexual and reproductive health in the medical curriculum in Pakistan
International Nuclear Information System (INIS)
Afsar, H.A.; Sohani, S.; Younas, M.; Mohammad, S.
2006-01-01
Objective: To assess the knowledge of medical practitioners regarding management of selected reproductive tract infections, diagnosis of sexual dysfunction and identification of sexual abuse and to assess the attitudes and practices of health care providers regarding sexual and reproductive rights in order to recommend areas that need to be incorporated in a sexual and reproductive health curriculum. Design: A cross-sectional survey. Place and Duration of Study: From March to August 2003 in the District Turbat of Balochistan, Pakistan. Subject and Methods: Selected indicators of knowledge, attitudes and practices regarding sexual and reproductive health of primary care physicians were assessed using a pre-tested questionnaire and formal informal interviews. Variables were identified from the literature and previous in-depth interviews, and then formulated into respective questions. A Lichert scale marked from 1 to 5 was used for categorizing responses into agreed, neutral and disagreed. Descriptive statistics were computed using SPSS version 10 for windows. Qualitative interviews were translated and transcribed and analyzed according to pre-judged and emerging themes. Results: Out of 45 physicians interviewed, nearly half scored less than 50% in the knowledge section. Attitudes and practices assessed suggested a tendency to be judgmental, gender/rights discriminatory and with little provision for enabling clients to make their own decisions, so essential for quality sexual health service provision. Conclusion: Keeping in view the importance of the sexual health issues and a lack of ability of health care providers to handle it effectively, deficient areas of sexual health must be integrated into the medical curriculum. Medical educators have the responsibility to train physicians and other health professionals in the core competencies to improve the sexual and reproductive health of their communities. (author)
-
Sexual Function and Marital Satisfaction in Female with Obsessive-Compulsive Disorder
Directory of Open Access Journals (Sweden)
Firoozeh Raeisi
2016-07-01
Full Text Available Abstract Background: Considering the high prevalence of sexual dysfunction in females with OCD and its impact on marital satisfaction, the purpose of this study was to investigate the relationship between sexual function and marital satisfaction in a group of female OCD patients. Materials and Methods: In this cross-sectional study, 36 females with OCD, referred to the clinic of Roozbeh Psychiatric Hospital (related to Tehran University of Medical Sciences and 3 private offices in Tehran, were selected by random sampling and completed questionnaires including: demographic FSFI, BDI-II, MOCI, OCI-R and researcher-developed marital satisfaction questionnaire. Results: 80.6% of women reported sexual dysfunction. The results of studying sexual function questionnaire subscales was as following: 50 % low sexual desire, 58.3 % low sexual arousal, 36.1 % decreased lubrication, 44 % orgasmic disorder, 52.8 % sexual pain disorder and 41.7 % sexual dissatisfaction. Furthermore, statistically significant correlation was found between sexual dysfunction (total score and arousal, lubrication, pain and satisfaction subscales and marital dissatisfaction. Studying the relation between obession(MOCI questionnaire and marital satisfaction revealed that the correlation between washing subscale of MOCI and marital dissatisfaction was also significant while there were not any significant correlation between obsession (OCJ-R, MOCI and sexual function (FSFI. Conclusion: High prevalence of sexual dysfunction in OCD patients, significant relationship between obsession and marital satisfaction, and sexual function and marital satisfaction could demonstrate relationship between sexual function, OCD and marital satisfaction.
-
Survival Processing Enhances Visual Search Efficiency.
Cho, Kit W
2018-05-01
Words rated for their survival relevance are remembered better than when rated using other well-known memory mnemonics. This finding, which is known as the survival advantage effect and has been replicated in many studies, suggests that our memory systems are molded by natural selection pressures. In two experiments, the present study used a visual search task to examine whether there is likewise a survival advantage for our visual systems. Participants rated words for their survival relevance or for their pleasantness before locating that object's picture in a search array with 8 or 16 objects. Although there was no difference in search times among the two rating scenarios when set size was 8, survival processing reduced visual search times when set size was 16. These findings reflect a search efficiency effect and suggest that similar to our memory systems, our visual systems are also tuned toward self-preservation.
-
Clarke, Michael J; Marks, Anthony D G; Lykins, Amy D
2015-01-01
Male sexual dysfunction is a prevalent and distressing condition, which may be exacerbated by the sufferer's perceptions of masculinity and normative sexual behavior. This study sought to investigate the effect of social context on males' beliefs regarding sexual behavior. The research examined the effect of male role modeling and masculine cues on males' dysfunctional sexual beliefs, sexual attitudes, and self-perceptions of sexual functioning. A sample of 140 male participants, with a mean age of 29 years, was exposed to pictorial and verbal cues that presented different versions of male behavior across three conditions. Results indicated that males exposed to models and cues of traditional masculinity showed significantly increased levels of dysfunctional sexual beliefs and traditional sexual attitudes relative to males exposed to models of modern masculinity. Results also indicated that males exposed to traditional masculine stimuli reported lower levels of sexual inhibition due to fear of performance failure than males exposed to models of modern masculinity. The potential role of social context is discussed in the development and maintenance of male sexual dysfunction and its implications for treatment.
-
Gaioso, Vanessa Pirani; Villarruel, Antonia Maria; Wilson, Lynda Anne; Azuero, Andres; Childs, Gwendolyn Denice; Davies, Susan Lane
2015-01-01
OBJECTIVE: to test a theoretical model based on the Parent-Based Expansion of the Theory of Planned Behavior examining relation between selected parental, teenager and cultural variables and Latino teenagers' intentions to engage in sexual behavior. METHOD: a cross-sectional correlational design based on a secondary data analysis of 130 Latino parent and teenager dyads. RESULTS: regression and path analysis procedures were used to test seven hypotheses and the results demonstrated partial support for the model. Parent familism and knowledge about sex were significantly associated with parents' attitudes toward sexual communication with their teenagers. Parent Latino acculturation was negatively associated with parents' self-efficacy toward sexual communication with their teenagers and positevely associated with parents' subjective norms toward sexual communication with their teenagers. Teenager knowledge about sex was significantly associated with higher levels of teenagers' attitudes and subjective norms about sexual communication with parents. Only the predictor of teenagers' attitudes toward having sex in the next 3 months was significantly associated with teenagers' intentions to have sex in the next 3 months. CONCLUSION: the results of this study provide important information to guide future research that can inform development of interventions to prevent risky teenager sexual behavior among Latinos. PMID:26312635
-
Pornography and sexual experiences among high school students in Sweden.
Mattebo, Magdalena; Tydén, Tanja; Häggström-Nordin, Elisabet; Nilsson, Kent W; Larsson, Margareta
2014-04-01
The study investigated the differences between high school boys and girls in: (1) the use of pornography, (2) sexual experiences, (3) experience of sexual abuse, and (4) perceptions of sexuality and pornography. It also examined the possible predictors of experiencing sexual activities, such as sex, sociodemographic factors (high school program, household, and ethnic background), pornography consumption, experience of sexual abuse, perception of sexuality, and perception of pornography. A population-based classroom survey of 16-year-old boys (n = 477) and girls (n = 400) from 53 randomly selected high school classes in 2 towns in mid-Sweden. Almost all boys (96%, n = 453) and 54% of the girls (n = 213) had watched pornography. Regardless of sex, pornography consumers had a positive perception of pornography. There were no differences between pornography-consuming boys and girls regarding fantasies, and they had attempted sexual acts inspired by pornography. A higher proportion of girls (15%) than boys (6%) had experienced sexual abuse. Predictors for being sexually experienced (oral sex, intercourse, and anal sex) included: being a girl, attending a vocational high school program, living with separated parents, having experience of sexual abuse, stating that boys and girls are equally interested in sex, and having a positive perception of pornography (Adj. R = 0.166). Boys had more experience of and a more positive perception of pornography, but there were only a few differences between boys and girls in the pornography-consumer group. Girls were more sexually experienced than boys. A positive perception of pornography predicted being sexually experienced.
-
Chadwick, Sara B; Burke, Shannon M; Goldey, Katherine L; Bell, Sarah N; van Anders, Sari M
2017-11-01
Sexual desire is increasingly understood to be multifaceted and not solely erotically oriented, but measures are still generally unitary and eroticism-focused. Our goals in this article were to explore the multifaceted nature of sexual desire and develop a measure to do so, and to determine how multifaceted sexual desire might be related to gender/sex and sexual orientation/identity. In the development phase, we generated items to form the 65-item Sexual Desire Questionnaire (DESQ). Next, the DESQ was administered to 609 women, 705 men, and 39 non-binary identified participants. Results showed that the DESQ demonstrated high reliability and validity, and that sexual desire was neither unitary nor entirely erotic, but instead was remarkably multifaceted. We also found that multifaceted sexual desire was in part related to social location variables such as gender/sex and sexual orientation/identity. We propose the DESQ as a measure of multifaceted sexual desire that can be used to compare factor themes, total scores, and scores across individual items in diverse groups that take social context into account. Results are discussed in light of how social location variables should be considered when making generalizations about sexual desire, and how conceptualizations of desire as multifaceted may provide important insights.
-
DEFF Research Database (Denmark)
Giles, James
Through a series of interrelated essays, this book explores fundamental issues concerning gender, sexual and romantic attraction, sexual desire and fantasies, the sexual positions, age dysphoria, and the role of naked skin in human sexuality. It does so by exploring experiential, social, biological...... on sex. It is further argued that sexual desire is an existential need based on the experience of having a gendered body. A case study of age dysphoria is presented showing how the conclusions concerning concerning gender and desire apply in an atypical case. The body's fundamental role in sexuality......, and evolutionary aspects of sexual life. The author criticizes several popular views, rejecting both social constructionist accounts of gender and social constructionist and biological accounts of sexual desire. It is argued instead that gender roles and gender are often confused and that gender itself is based...
-
Simons, Mirre J. P.; Briga, Michael; Koetsier, Egbert; Folkertsma, Remco; Wubs, Matthias D.; Dijkstra, Cor; Verhulst, Simon
2012-01-01
Sexual traits can serve as honest indicators of phenotypic quality when they are costly. Brightly coloured yellow to red traits, which are pigmented by carotenoids, are relatively common in birds, and feature in sexual selection. Carotenoids have been linked to immune and antioxidant function, and
-
Prioritization of Potential Mates' History of Sexual Fidelity During a Conjoint Ranking Task.
Mogilski, Justin K; Wade, T Joel; Welling, Lisa L M
2014-07-01
This series of studies is the first to use conjoint analysis to examine how individuals make trade-offs during mate selection when provided information about a partner's history of sexual infidelity. Across three studies, participants ranked profiles of potential mates, with each profile varying across five attributes: financial stability, physical attractiveness, sexual fidelity, emotional investment, and similarity. They also rated each attribute separately for importance in an ideal mate. Overall, we found that for a long-term mate, participants prioritized a potential partner's history of sexual fidelity over other attributes when profiles were ranked conjointly. For a short-term mate, sexual fidelity, physical attractiveness, and financial stability were equally important, and each was more important than emotional investment and similarity. These patterns contrast with participants' self-reported importance ratings of each individual attribute. Our results are interpreted within the context of previous literature examining how making trade-offs affect mate selection. © 2014 by the Society for Personality and Social Psychology, Inc.
-
Effects of hyperthyroidism, hypothyroidism, and thyroid autoimmunity on female sexual function.
Oppo, A; Franceschi, E; Atzeni, F; Taberlet, A; Mariotti, S
2011-06-01
Thyroid hormones affect male and female sexual functions, but data in hypo- and hyperthyroid women are scanty. To investigate sexual function in hypo- and hyperthyroid women before and immediately after restoration of euthyroidism and in women with euthyroid Hashimoto's thyroiditis (HT). Fifty-six women with thyroid diseases (age 19-50 yr; 22 with hyperthyroidism, 17 with hypothyroidism, and 17 with euthyroid HT) and 30 age-matched healthy women. Hypoactive sexual desire, disorders of sexual arousal, vaginal lubrication, orgasm, satisfaction, and sexual pain (SPD) were assessed by Female Sexual Function Index. Serum TSH, free T4 (FT4) and thyroid autoantibodies (anti-thyroglobulin, anti-thyroperoxidase, and TSH-receptor antibodies) were assessed at the diagnosis; FT4 and TSH were repeated after treatment to confirm normalization of thyroid function. All sexual domains scores were significantly reduced (p ranging hyperthyroid women. Correction of hypothyroidism was associated to normalization of desire, satisfaction, and pain, while arousal and orgasm remained unchanged. In hyperthyroid women therapy normalized sexual desire, arousal/lubrication, satisfaction, and pain, while orgasm remained significantly impaired. Interestingly, euthyroid HT women displayed a significant decrease in sexual desire (phyperthyroidism markedly impair female sexual function. A rapid improvement is observed with the restoration of euthyroidism, although a longer period of time may be needed for full normalization. Preliminary data suggest that thyroid autoimmunity may selectively impair sexual desire, independently from thyroid function.
-
Teenage sexuality and rights in Chile: from denial to punishment.
Casas, Lidia; Ahumada, Claudia
2009-11-01
While Chile sees itself as a country that has fully restored human rights since its return to democratic rule in 1990, the rights of teenagers to comprehensive sexuality education are still not being met. This paper reviews the recent history of sexuality education in Chile and related legislation, policies and programmes. It also reports a 2008 review of the bylaws of 189 randomly selected Chilean schools, which found that although such bylaws are mandatory, the absence of bylaws to prevent discrimination on grounds of pregnancy, HIV and sexuality was common. In relation to how sexual behaviour and discipline were addressed, bylaws that were non-compliant with the law were very common. Opposition to sexuality education in schools in Chile is predicated on the denial of teenage sexuality, and many schools punish sexual behaviour where transgression is perceived to have taken place. While the wider Chilean society has been moving towards greater recognition of individual autonomy and sexual diversity, this cultural shift has yet to be reflected in the government's political agenda, in spite of good intentions. Given this state of affairs, the Chilean polity needs to recognise its youth as having human rights, or will continue to fail in its commitment to them.
-
Sexual learning, sexual experience, and healthy adolescent sex.
Fortenberry, J Dennis
2014-01-01
This chapter is organized around the question "How do adolescents learn to have healthy sex?" The chapter assumes that sexual learning derives from a broad range of both informal and formal sources that contribute to learning within the context of neurocognitive brain systems that modulate sexual motivations and self-regulation. The overall objective is to consider how adolescents become sexually functional and healthy and to provide a conceptual basis for expansion of sexual learning to better support healthy sexual functioning. © 2014 Wiley Periodicals, Inc.
-
Exploratory study of Australian aged care staff knowledge and attitudes of later life sexuality.
Chen, Yung-Hui; Jones, Cindy; Osborne, Debora
2017-06-01
To explore aged care staff knowledge and attitudes towards later life sexuality and attitudes about intimacy in people with dementia. Fifty-two care staff working in two aged care facilities with secure dementia care units were recruited. Knowledge and attitudes on later life sexuality and attitudes towards later life sexuality in people with dementia were surveyed using the Aging Sexual Knowledge and Attitudes Scale and the selected eight items of the Staff Attitudes about Intimacy and Dementia, respectively. The results indicated that aged care staff knowledge of later life sexuality is inadequate, but attitudes towards later life sexuality and about intimacy and dementia were relatively permissive. Improving aged care staff knowledge of later life sexuality is needed. Continuing education and training should provide to support the expression of later life sexuality including those with dementia. © 2017 AJA Inc.
-
Outcomes of Sexual Behaviors among Sexual Minority Youth
Morgan, Elizabeth M.
2014-01-01
Very little is known about outcomes of sexual behavior for sexual minority youth. In this chapter, I review relevant literature and draw on findings from my own research to initiate an inquiry into this important topic. I begin with a brief overview of the range of sexual behaviors of sexual minority adolescents and young adults. Next, I describe…
-
Ginsberg, Terrie B
2010-05-01
It should be recognized that sexuality in the aging male is of such import that a complete sexual history must be performed. By taking a complete sexual history, facts can be obtained that will allow for appropriate focus relating to a holistic evaluation and will enable us to dispel antiquated sexual myths pertaining to the aging male. If initiated by the history taker, questions concerning sexuality may be discussed more comfortably by the patient. Erectile dysfunction, male sexual response cycle, testosterone, sexually transmitted diseases, human immunodeficiency virus, long-term illness, along with religion and culture are explored in this article with the aim of improving one's knowledge base, self reflection, and awareness of the importance of male sexuality. A complete understanding and appreciation of the aging male's medical history, surgical history, social history, and emotional history as well as his sexual, cultural, and religious concepts will allow the health care provider to better analyze information, and to recommend and provide appropriate advice and treatment to the aging male patient. Copyright 2010 Elsevier Inc. All rights reserved.
-
The implications of sexual narcissism for sexual and marital satisfaction.
McNulty, James K; Widman, Laura
2013-08-01
There is theoretical reason to believe narcissism is associated with a number of sexual behaviors and outcomes that affect both sexual and relationship satisfaction. Nevertheless, research on the association between personality and behavior demonstrates that personality traits, such as narcissism, only predict behavior in domains that activate the components of the personality system. Given that global assessments of narcissism do not capture the extent to which the components of narcissism are activated in the sexual domain, we examined the extent to which the facets of a domain-specific measure of sexual narcissism accounted for the trajectories of own and partner sexual and marital satisfaction over the first five years of 120 new marriages. Three of the four facets of sexual narcissism (sexual exploitation, sexual entitlement, and low sexual empathy) were negatively associated with both trajectories. The fourth facet (sexual skill) was positively associated with both trajectories. Notably, sexual satisfaction mediated the effect of every facet of sexual narcissism on marital satisfaction. A global assessment of narcissism was not associated with either trajectory of satisfaction. These findings highlight (1) the importance of narcissistic tendencies for sexual processes, (2) the benefits of using domain-specific measures of personality in research on sexual behavior, and (3) the importance of examining the implications of the specific facets of personality constructs.
-
The Implications of Sexual Narcissism for Sexual and Marital Satisfaction
McNulty, James K.; Widman, Laura
2013-01-01
There is theoretical reason to believe narcissism is associated with a number of sexual behaviors and outcomes that affect both sexual and relationship satisfaction. Nevertheless, research on the association between personality and behavior demonstrates that personality traits, such as narcissism, only predict behavior in domains that activate the components of the personality system. Given that global assessments of narcissism do not capture the extent to which the components of narcissism are activated in the sexual domain, we examined the extent to which the facets of a domain-specific measure of sexual narcissism accounted for the trajectories of own and partner sexual and marital satisfaction over the first five years of 120 new marriages. Three of the four facets of sexual narcissism (sexual exploitation, sexual entitlement, and low sexual empathy) were negatively associated with both trajectories. The fourth facet (sexual skill) was positively associated with both trajectories. Notably, sexual satisfaction mediated the effect of every facet of sexual narcissism on marital satisfaction. A global assessment of narcissism was not associated with either trajectory of satisfaction. These findings highlight (1) the importance of narcissistic tendencies for sexual processes, (2) the benefits of using domain-specific measures of personality in research on sexual behavior, and (3) the importance of examining the implications of the specific facets of personality constructs. PMID:23297145
-
[Social transformation of sexuality in the past decades. An overview].
Sigusch, V
2000-03-01
The societies of the Western world have witnessed a tremendous cultural and social transformation of sexuality during the eighties and nineties, a process Sigusch refers to as "the neosexual revolution". Up to now, this transformation and reassessment of sexuality has proceeded rather slowly and quietly. Yet both its real and its symbolic effects may indeed be more consequential that those brought about in the course of the rapid, noisy sexual revolution of the sixties and seventies. The neosexual revolution is dismantling the old patterns of sexuality and reassembling them anew. In the process, dimensions, intimate relationships, preferences and sexual fragments emerge, many of which had submerged, were unnamed or simply did not exist before. In general, sexuality has lost much of its symbolic meaning as a cultural phenomenon. Sexuality is no longer the great metaphor for pleasure and happiness, nor is it so greatly overestimated as it was during the sexual revolution. It is now widely taken for granted, much like egotism or motility. Whereas sex was once mystified in a positive sense--as ecstasy and transgression, it has now taken on a negative mystification characterized by abuse, violence and deadly infection. While the old sexuality was based primarily upon sexual instinct, orgasm and the heterosexual couple, neosexualities revolve predominantly around gender difference, thrills, self-gratification and prosthetic substitution. From the vast number of interrelated processes from which neosexualities emerge, three phenomena have been selected for discussion here: the dissociation of the sexual sphere, the dispersion of sexual fragments and the diversification of sexual relationships. The outcome of the neosexual revolution could be described as self-disciplined and self-optimized "self-sex".
-
Lykins, Amy D; Janssen, Erick; Newhouse, Sarah; Heiman, Julia R; Rafaeli, Eshkol
2012-05-01
Despite the importance of sexuality for romantic relationships, there has been little research attention to individual differences and dyadic variables, including couple similarity, and their association with sexual problems and satisfaction. The current study examined the effects of the propensity for sexual inhibition and sexual excitation scales (SIS/SES) and the effects of different mood states on sexuality (Mood and Sexuality Questionnaire [MSQ]), at both the individual and the dyad level, on sexual arousal problems and sexual satisfaction. Similarity in SIS/SES and MSQ was measured in a nonclinical sample of 35 newlywed couples and operationally defined as the within-couple, z-transformed correlations between the two partners' item responses. Sexual arousal problems were assessed using self-report measures (Demographic and Sexual History Questionnaire) and focused on the past 3 months. Sexual satisfaction was assessed using the Global Measure of Sexual Satisfaction. Regression analyses revealed that greater similarity in the effects of anxiety and stress on sexuality was associated with more reported sexual arousal problems of wives. In contrast, the husbands' sexual arousal problems were related only to their own higher SIS1 scores. Higher SES scores predicted lower sexual satisfaction for both husbands and wives. Wives who reported strong positive mood effects on their sexuality indicated greater sexual satisfaction, while husbands who were more similar to their wives in the effect of positive moods on sexuality indicated greater sexual satisfaction. The findings show that, above and beyond one's own sexual propensities, similarity in various aspects of sexuality predicts sexual problems (more so in women) and sexual satisfaction (in both men and women). © 2012 International Society for Sexual Medicine.
-
Simon, Valerie A.; Feiring, Candice
2008-01-01
Youth with confirmed histories of sexual abuse (N = 118) were followed longitudinally to examine associations between their initial sexual reactions to abuse and subsequent sexual functioning. Participants were interviewed at abuse discovery (ages 8 through 15) and again 1 and 6 years later. Eroticism and sexual anxiety emerged as distinct indices of abuse-specific sexual reactions and predicted subsequent sexual functioning. Eroticism was associated with indicators of heightened sexuality, i...
-
Hsu, Hsiu-Yueh; Yu, Hsing-Yi; Lou, Jiunn-Horng; Eng, Cheng-Joo
2015-04-01
Sexual self-efficacy plays an important role in adolescents' sexual health. The aim of this study was to test a cause-and-effect model of sexual self-concept and sexual risk cognition toward sexual self-efficacy in adolescents. The study was a cross-sectional survey. Using a random sampling method, a total of 713 junior nursing students were invited to participate in the study, and 465 valid surveys were returned, resulting in a return rate of 65.2%. The data was collected using an anonymous mailed questionnaire. Structural equation modeling was used to test the relationships among sexual self-concept, sexual risk cognition, and sexual self-efficacy, as well as the mediating role of sexual risk cognition. The results revealed that the postulated model fits the data well. Sexual self-concept significantly predicted sexual risk cognition and sexual self-efficacy. Sexual risk cognition significantly predicted sexual self-efficacy and had a mediating effect on the relationship between sexual self-concept and sexual self-efficacy. Based on social cognitive theory and a structural equation model technique, this study confirmed the mediating role of sexual risk cognition in the relationship between sexual self-concept and sexual self-efficacy. Also, sexual self-concept's direct and indirect effects explaining adolescents' sexual self-efficacy were found in this study. © 2014 The Authors. Japan Journal of Nursing Science © 2014 Japan Academy of Nursing Science.
-
Directory of Open Access Journals (Sweden)
Júlio Cezar Uili Coelho
2003-01-01
Full Text Available OBJETIVO: Avaliar a qualidade de vida sexual masculina antes e depois do transplante hepático. MÉTODOS: Foi enviado questionário de avaliação para 56 doentes masculinos, que tinham idade superior a 18 anos e que sobreviveram mais de seis meses após o transplante hepático. O questionário continha 15 perguntas com cinco ou seis alternativas de resposta para mensurar a função sexual masculina segmentada por cinco componentes: função erétil, função orgástica, desejo sexual, satisfação com a relação sexual e satisfação com a vida sexual como um todo. As respostas geraram valores numéricos, os quais foram agrupados dentro de cada domínio e comparados antes e depois do transplante hepático. RESULTADOS: Vinte e cinco doentes responderam completamente o questionário. Todas os cinco componentes da função sexual melhoraram após o transplante hepático, sendo que o escore da função erétil aumentou de 21,12±8,07 para 26,52±5,22 (p=0,004, da função orgástica de 7,28±3,05 para 9,36±1,47 (p=0,008, da função desejo sexual de 6,64±2,58 para 8,68±1,35 (p=0,005, da satisfação com relação sexual de 9,16±3,83 para 12,52±2,65 (pBACKGROUND: Sexual dysfunction is very common in liver transplantation candidates. Our objective is to determine the sexual life quality of males before and after liver transplantation. METHODS: Questionnaire was sent to 56 males over 18 years of age with at least six-month survival after orthotopic liver transplantation. The self-administered questionnaire contained 15 questions with 5 or 6 alternatives to determine the male sexual function which may be divided into 5 domains: 1 erectile function; 2 orgasmic function; 3 sexual desire; 4 intercourse satisfaction; and 5 overall satisfaction with sexual life. Each answer received a score. Domains scores were computed by summing the scores for individual answers and they were compared before and after the liver transplantation. RESULTS: Twenty
-
Causes of Sexual Promiscuity Among Female Undergraduate ...
African Journals Online (AJOL)
This study investigated causes of sexual promiscuity among female undergraduate students in university of Lagos. The sample comprised 150 female undergraduate students randomly selected from all the five female hostels in University of Lagos. A researcher-constructed questionnaire was administered to test the three ...
-
Morais, Hugo B; Alexander, Apryl A; Fix, Rebecca L; Burkhart, Barry R
2018-02-01
Most studies on the mental health consequences of childhood sexual abuse (CSA) focus predominantly on CSA survivors who do not commit sexual offenses. The current study examined the effects of CSA on 498 male adolescents adjudicated for sexual offenses who represent the small portion of CSA survivors who engage in sexual offenses. The prevalence of internalizing symptoms, parental attachment difficulties, specific sexual offending behaviors, and risk for sexually offending were compared among participants with and without a history of CSA. Results indicated that participants with a history of CSA were more likely to be diagnosed with major depression and posttraumatic stress disorder than those who did not report a history of CSA. A history of CSA was also positively correlated with risk for sexually offending and with specific offense patterns and consensual sexual behaviors. No significant differences emerged on parental attachment difficulties. These results highlight that adolescents adjudicated for sexual offenses with a history of CSA present with differences in sexual and psychological functioning as well as markedly different offending patterns when compared with those without a CSA history. Clinical implications and future directions are discussed.
-
Social selection is a powerful explanation for prosociality.
Nesse, Randolph M
2016-01-01
Cultural group selection helps explain human cooperation, but social selection offers a complementary, more powerful explanation. Just as sexual selection shapes extreme traits that increase matings, social selection shapes extreme traits that make individuals preferred social partners. Self-interested partner choices create strong and possibly runaway selection for prosocial traits, without requiring group selection, kin selection, or reciprocity.
-
Differences in Risky Sexual Behavior According to Sexual Orientation in Korean Adolescents.
Kim, Ji-Su; Kim, Kyunghee; Kwak, Yeunhee
2017-10-13
Adolescents in sexual minority groups are known to be at risk of contracting sexually transmitted diseases through risky sexual behavior. However, few studies have examined associations between sexual orientation and risky sexual behavior and sexually transmitted diseases in Korean adolescents. Therefore, this cross-sectional study used raw data from the Tenth Korea Youth Risk Behavior Web-Based Survey to explore these relationships. Logistic regression analyses were performed to examine the associations between risky sexual behavior and sexual orientation in adolescents. The participants were 6,884 adolescents who provided data regarding demographic characteristics, sexual orientation, and risky sexual behavior. The proportions of homosexual and bisexual subjects who used condoms, engaged in sexual intercourse after drinking alcohol, and experienced sexually transmitted diseases were higher relative to those of heterosexual subjects. Associations between homosexuality and bisexuality and sexually transmitted diseases and engagement in sexual intercourse after drinking remained after multivariate adjustment. Interventions to prevent risky sexual behavior should target sexual orientation, to improve sexual health and prevent sexually transmitted disease in homosexual and bisexual adolescents.
-
Rethinking Sexual Citizenship.
Richardson, Diane
2017-04-01
Over the last two decades sexuality has emerged as a key theme in debates about citizenship, leading to the development of the concept of sexual citizenship. This article reviews this literature and identifies four main areas of critical framing: work that contests the significance of sexuality to citizenship; critiques that focus on the possibilities and limitations of mobilising the language of citizenship in sexual politics; analyses of sexual citizenship in relation to nationalisms and border making; and literature that critically examines western constructions of sexuality and sexual politics underpinning understandings of sexual citizenship. In order to progress the field theoretically, the article seeks to extend critiques of sexual citizenship focusing on two key aspects of its construction: the sexual citizen-subject and spaces of sexual citizenship. It argues for a critical rethink that encompasses a de-centring of a 'western-centric' focus in order to advance understandings of how sexual citizenship operates both in the Global North and South.
-
Richardson, Diane
2016-01-01
Over the last two decades sexuality has emerged as a key theme in debates about citizenship, leading to the development of the concept of sexual citizenship. This article reviews this literature and identifies four main areas of critical framing: work that contests the significance of sexuality to citizenship; critiques that focus on the possibilities and limitations of mobilising the language of citizenship in sexual politics; analyses of sexual citizenship in relation to nationalisms and border making; and literature that critically examines western constructions of sexuality and sexual politics underpinning understandings of sexual citizenship. In order to progress the field theoretically, the article seeks to extend critiques of sexual citizenship focusing on two key aspects of its construction: the sexual citizen-subject and spaces of sexual citizenship. It argues for a critical rethink that encompasses a de-centring of a ‘western-centric’ focus in order to advance understandings of how sexual citizenship operates both in the Global North and South. PMID:28490816
-
Sexual offending runs in families: A 37-year nationwide study.
Långström, Niklas; Babchishin, Kelly M; Fazel, Seena; Lichtenstein, Paul; Frisell, Thomas
2015-04-01
Sexual crime is an important public health concern. The possible causes of sexual aggression, however, remain uncertain. We examined familial aggregation and the contribution of genetic and environmental factors to sexual crime by linking longitudinal, nationwide Swedish crime and multigenerational family registers. We included all men convicted of any sexual offence (N = 21,566), specifically rape of an adult (N = 6131) and child molestation (N = 4465), from 1973 to 2009. Sexual crime rates among fathers and brothers of sexual offenders were compared with corresponding rates in fathers and brothers of age-matched population control men without sexual crime convictions. We also modelled the relative influence of genetic and environmental factors to the liability of sexual offending. We found strong familial aggregation of sexual crime [odds ratio (OR) = 5.1, 95% confidence interval (CI) = 4.5-5.9] among full brothers of convicted sexual offenders. Familial aggregation was lower in father-son dyads (OR = 3.7, 95% CI = 3.2-4.4) among paternal half-brothers (OR = 2.1, 95% CI = 1.5-2.9) and maternal half-brothers (OR = 1.7, 95% CI = 1.2-2.4). Statistical modelling of the strength and patterns of familial aggregation suggested that genetic factors (40%) and non-shared environmental factors (58%) explained the liability to offend sexually more than shared environmental influences (2%). Further, genetic effects tended to be weaker for rape of an adult (19%) than for child molestation (46%). We report strong evidence of familial clustering of sexual offending, primarily accounted for by genes rather than shared environmental influences. Future research should possibly test the effectiveness of selective prevention efforts for male first-degree relatives of sexually aggressive individuals, and consider familial risk in sexual violence risk assessment.