Female Choice Research Articles

The origins and drivers of sexual size dimorphism in sharks.

While sexual size dimorphism (SSD) is abundant in nature, there is huge variation in both the intensity and direction of SSD. SSD results from a combination of sexual selection for large male size, fecundity selection for large female size and ecological selection for either. In most vertebrates, it is variation in the intensity of male-male competition that primarily underlies variation in SSD. In this study, we test four hypotheses regarding the adaptive value of SSD in sharks-considering the potential for each of fecundity, sexual, ecological selection and reproductive mode as the primary driver of variation in SSD between species. We also estimate past macroevolutionary shifts in SSD direction/intensity through shark phylogeny. We were unable to find evidence of significant SSD in early sharks and hypothesise that SSD is a derived state in this clade, that has evolved independently of SSD observed in other vertebrates. Moreover, there is no significant relationship between SSD and fecundity, testes mass or oceanic depth in sharks. However, there is evidence to support previous speculation that reproductive mode is an important determinant of interspecific variation in SSD in sharks. This is significant as in most vertebrates sexual selection is thought to be the primary driver of SSD trends, with evidence for the role of fecundity selection in other clades being inconsistent at best. While the phylogenetic distribution of SSD among sharks is superficially similar to that observed in other vertebrate clades, the relative importance of selective pressures underlying its evolution appears to differ.

How much multiple paternity should we expect? A study of birds and contrast with mammals.

Parentage analyses via molecular markers have revealed multiple paternity within the broods of polytocous species, reshaping our understanding of animal behavior, ecology, and evolution. In a meta-analysis of multiple paternity in bird and mammal species, we conducted a literature search and found 138 bird and 64 mammal populations with microsatellite DNA paternity results. Bird populations averaged 19.5% multiple paternity and mammals more than twice that level (46.1%). We used a Bayesian approach to construct a null model for how multiple paternity should behave at random among species, under the assumption that all mated males have equal likelihood of siring success, given mean brood size and mean number of sires. We compared the differences between the null model and the actual probabilities of multiple paternity. While a few bird populations fell close to the null model, most did not, averaging 34.0-percentage points below null model predictions; mammals had an average probability of multiple paternity 13.6-percentage points below the null model. Differences between bird and mammal species were also subjected to comparative phylogenetic analyses that generally confirmed our analyses that did not adjust for estimated historical relationships. Birds exhibited extremely low probabilities of multiple paternity, not only compared to mammals but also relative to other major animal taxa. The generally low probability of multiple paternity in birds might be produced by a variety of factors, including behaviors that reflect sexual selection (extreme mate guarding or unifocal female choice) and sperm competition (e.g., precedence effects favoring fertilization by early or late matings).

Is syllable repetitions a song parameter important for male-male interactions in Eurasian reed warbler (Acrocephalus scirpaceus)?

Song complexity has been identified as one song characteristic important in female choice, whereas its role in male-male interactions is less clear and not much is known which song characteristics are specifically important for territorial defense. In Acrocephalus warblers, males seem to increase song complexity towards females but reduce it during territorial disputes. One possibility to reduce song complexity could be achieved by repeating individual syllables. In this context here we examined the importance of males repeating syllables in male-male interactions. We hypothesis that repeating syllables signals a males general fighting ability, aggressive status or willingness to attack. In a playback experiment we investigated the behavioral response of unmated, territorial Eurasian reed warbler (Acrocephalus scirpaceus) males towards two simultaneously singing intruders whereby the song of the two simulated intruders differs in the degree of syllable repetitions. The response of the territory owner was determined by using several behavioral parameters. Our results revealed that males approached faster and stayed significantly longer near the song with few syllable repetitions. However, the proportion of males approaching the song with high or low syllable repetitions first, as well as the minimal distance to which males approach to the two song types did not differ as well. Thus, the weaker response towards the high repetitive song playback suggests territorial males to be more intimidated by the aggressive nature of that song type.

Ketika kekerasan dianggap seksi: persepsi laki-laki bahwa perempuan suka kekerasan memicu pola pikir ekstremis militan

Inspired by the paradigm of mate selection motives in evolutionary psychology, this research seeks to determine the extent to which violent extremist thought patterns are a product of perceptions of attractiveness that persist in men as a response to intrasexual selection. The survey was conducted on 192 samples of the general population in Indonesia, on a male sample (n = 80), after controlling for demographic variables, including dark personality (dark triad), men's subjective perception that Indonesian women find violence attractive (PAOSV) predicts militant-extremist mindset. PAOSV was the only variable that predicted violent extremism mindset in men. Furthermore, we discovered a mechanism that we call “sexualization of violence” – namely the extent to which individuals perceive violence as sexy, manly, and cool (AV) as a process that arises from the perception of high levels of positive feedback from the opposite sex towards violence. Where in the sample of men in this study, the only variable that shaped the mindset of violent extremism was sexual motives. The discussion elaborate differences in perceptions of attraction to violence between men and women, differentiation and gaps in perceptions between men and women in assessing violence. This study has practical implications, namely discussing the importance of the role of women as active agents in the formation of a culture of nonviolence.

Video evidence of mountings by female‐plumaged birds of paradise (Aves: Paradisaeidae) in the wild: Is there evidence of alternative mating tactics?

AbstractThe bewildering courtship phenotypes of male birds of paradise (Paradisaedae) represent a classic example of sexual selection through mate choice. While the majority of sexual selection studies have focused on either mate choice or intrasexual competition, males across a variety of taxa adopt alternative mating tactics as additional means of obtaining fertilization when they are otherwise unable to. For example, across various polygynous birds, subordinate males engage in sneak copulations, which may offset the fitness costs of prolonged subordinate periods. Despite exhibiting strong mating skews and male delayed plumage maturation, reports of sneak copulation in the birds of paradise are exceedingly rare. After reviewing an extensive video collection of courtship interactions, we found examples of mountings by female‐plumaged birds in three birds of paradise species: the Western parotia Parotia sefilata, Carola's parotia Parotia carolae, and the magnificent bird of paradise Cicinnurus magnificus. While homosexual mountings by females have been documented previously in Lawes' parotia P. lawesii, adult males in the magnificent bird of paradise violently attacked intruding female‐plumaged birds attempting to mount receivers, suggesting that they may be immature males engaging in alternative mating tactics. Overall, the rare video footage described here is suggestive of two fascinating, yet unexplored phenomena in polygynous birds: alternative mating tactics and female homosexual behaviour.

Sex‐specific oviposition site selection in an arboreal treefrog with a resource‐defense mating system

AbstractOviposition site selection by parents is an important factor that affects offspring survival and parental fitness. The relative importance of sexes in oviposition site selection in anurans is rarely evaluated, especially in species with resource‐defense mating systems, where males defend territory containing eventual oviposition sites before advertising for females. Using a phytotelm‐breeding frog (Kurixalus eiffingeri) with male territoriality, we examined 310 bamboo stumps (potential for oviposition sites) to determine whether male and female choice of oviposition site based on physical characteristics (stump height, inner diameter, stump depth, water depth, and water volume). We found that males preferred a site with higher stumps that were deeper and contained more water, while females showed no preference for sites based on the characteristics observed. Although we do not exclude the possibility that K. eiffingeri female oviposition site selection can be relied on and/or correlates to male advertisement calls, this study is one of few studies to examine the role of both sexes in oviposition site selection simultaneously, and provides empirical evidence that oviposition site selection is primarily determined by males in an amphibian with a resource‐defense mating system.

Can females differentially allocate resources to offspring sired by different males?

Abstract The viviparity-driven conflict hypothesis postulates that the evolution of matrotrophy (postfertilization maternal provisioning) will result in a shift from a pre- to postcopulatory mate choice and thus accelerate the evolution of postcopulatory reproductive isolation. Here, we perform artificial insemination experiments on Heterandria formosa, a matrotrophic poeciliid fish, to probe for evidence of postcopulatory female choice. We established laboratory populations from Wacissa River (WR) and Lake Jackson (LJ). The WR females normally produce larger offspring than the LJ females. We artificially inseminated females with sperm from each population or from both populations simultaneously. When LJ females were inseminated with sperm from WR and LJ males, they allocated fewer resources to WR-sired offspring than when they were inseminated with WR sperm alone. The LJ females carrying developing offspring sired by males from different populations were thus able to discriminate against non-resident males when allocating resources to developing young. The WR females, which normally produce larger offspring than LJ females, did not discriminate among males from different localities. These findings provide insights into the ability of females from one population to exercise a form of postcopulatory mate selection.

Flanged males have higher reproductive success in a completely wild orangutan population.

Male orangutans (Pongo spp.) exhibit bimaturism, an alternative reproductive tactic, with flanged and unflanged males displaying two distinct morphological and behavioral phenotypes. Flanged males are larger than unflanged males and display secondary sexual characteristics which unflanged males lack. The evolutionary explanation for alternative reproductive tactics in orangutans remains unclear because orangutan paternity studies to date have been from sites with ex-captive orangutans, provisioning via feeding stations and veterinary care, or that lack data on the identity of mothers. Here we demonstrate, using the first long-term paternity data from a site free of these limitations, that alternative reproductive tactics in orangutans are condition-dependent, not frequency-dependent. We found higher reproductive success by flanged males than by unflanged males, a pattern consistent with other Bornean orangutan (Pongo pygmaeus) paternity studies. Previous paternity studies disagree on the degree of male reproductive skew, but we found low reproductive skew among flanged males. We compare our findings and previous paternity studies from both Bornean and Sumatran orangutans (Pongo abelii) to understand why these differences exist, examining the possible roles of species differences, ecology, and human intervention. Additionally, we use long-term behavioral data to demonstrate that while flanged males can displace unflanged males in association with females, flanged males are unable to keep other males from associating with a female, and thus they are unable to completely mate guard females. Our results demonstrate that alternative reproductive tactics in Bornean orangutans are condition-dependent, supporting the understanding that the flanged male morph is indicative of good condition. Despite intense male-male competition and direct sexual coercion by males, female mate choice is effective in determining reproductive outcomes in this population of wild orangutans.

No geographical differences in male mate choice in a widespread fish, Limia perugiae.

Behavior, like most other traits, can have a spatial component, and variability of behavior at the population level is predicted. In this article, we explore male mate choice at this level. Male mate choice, while maybe not as common as female choice, is expected to evolve when males respond to significant variation in female quality and, for example, prefer females with higher fecundity. In fishes, higher fecundity is associated with larger body size, an easily measured trait. In this study, we investigated the presence of male mate choice for larger females in a widespread species of livebearing fish, Limia perugiae, while comparing preferences between populations. We hypothesized that environmental variation, for example, in the form of salinity, might result in population differences. Using dichotomous choice tests, we analyzed behavioral data for 80 individuals from 7 distinct populations from Hispaniola. We found that L. perugiae males significantly preferred large females, but there was no significant statistical variation between populations.

Short-Term Changes in Vasectomy Consults and Procedures Following Dobbs v Jackson Women's Health Organization.

On June 24, 2022, the US Supreme Court issued its decision on Dobbs v Jackson Women's Health Organization (Dobbs). This decision had major implications on female reproductive choices, but also had potential implications on their male counterparts. We sought to determine the association of Dobbs with the number and characteristics of men seeking vasectomy. A retrospective review was performed to determine the number of vasectomy consults and procedures completed at a single Michigan health system in the 6 months following Dobbs (June 24, 2022-December 24, 2022) vs the same 6-month time frame between 2019 and 2021. Another retrospective review was conducted in the 3 months following Dobbs (June 24, 2022-September 24, 2022) vs the same days in 2021 to determine the number of vasectomy consults completed and to evaluate for differences in the characteristics of these men. In the 6 months after Dobbs, there was a 150% and 160% increase in vasectomy consults and procedures completed, respectively, compared to a similar time frame in 2019 to 2021. In the 3 months after Dobbs, there was a 225% increase in new vasectomy consults compared to a similar time frame in 2021. There were no differences in the age, race, religion, median household income, or insurance type of men seeking vasectomy consult pre- vs post-Dobbs. Partnerless men (odds ratio 3.66) and those without children (odds ratio 2.85) were more likely than married men and those with 3 or more children, respectively, to seek vasectomy consult post-Dobbs. Dobbs was associated with a marked increase in vasectomy consultations and procedures at our institution in the state of Michigan. Future studies are needed to determine the long-term implications of Dobbs on vasectomy practices and determine if vasectomy practices differ by states and their respective abortion laws.

Little evidence for color- or size-based mating preferences by male strawberry poison frogs (Oophaga pumilio)

While there are many studies documenting female mating preferences across taxa, male mate choice remains relatively understudied. Male mate choice often develops when there is variation in female quality and thus the fitness benefits of mating with particular females. Specifically, males tend to prefer females with traits that confer direct fitness benefits such as large body size, which may be linked with high fecundity. Prior work has shown that females of the strawberry poison frog, Oophaga pumilio, prefer males bearing certain coloration (most often the female’s own color), and that this preference can be learned through maternal imprinting. Females have been shown to prefer larger males as well. Here we test whether similar mate preferences for color and size exist in males of this species using two-way choice tests on captive bred male O. pumilio. In each test focal males were placed in an arena with two stimulus females: either both of the same size but differing in color, or both of the same color but differing in size. We found only weak evidence for behavioral biases toward particular colors and no evidence for biases toward larger females, suggesting that males of O. pumilio do not predictably choose mates based on these female traits. Despite several aspects of their natural history that suggest males have reasons to be choosy, our findings suggest that the cost of mate rejection may outweigh any fitness benefits derived from being selective of mates. Studies of additional populations, ideally conducted on wild individuals, are needed to better understand the range of conditions under which males may exhibit mate choice and the types of traits on which they base these choices.Significance statementTo fully understand the fitness landscapes and evolutionary trajectories that result from sexual selection, we need to understand when and how the mate preferences of the two sexes act and interact. While female mate choice has been widely studied, male mate choice remains poorly understood. To help bridge this gap, we studied male mate preferences in the strawberry poison frog Oophaga pumilio, a small brightly colored frog for which female preferences for male color and size have been well-documented. We found no evidence that male O. pumilio exhibit mate preferences based on female size and little evidence for male mate preferences based on female color. This is surprising given that larger females are often more fecund, male O. pumilio are known to exhibit color-based behavioral biases in the context of male-male competition, and both sexes provide parental care.

Male, female, and mixed-sex poplar plantations support divergent soil microbial communities.

Males and females of dioecious plants have sex-specific adaptations to diverse habitats. The effects of inter- and intrasexual interactions in poplar plantations on composition, structure, and function of soil microbiota have not been explored in degraded areas. We conducted a series of greenhouse and field experiments to investigate how belowground competition, soil microbial communities, and seasonal variation nitrogen content differ among female, male, and mixed-sex Populus cathayana plantations. In the greenhouse experiment, female neighbors suppressed the growth of males under optimal nitrogen conditions. However, male neighbors enhanced stable isotope ratio of nitrogen (δ15 N) of females under intersexual competition. In the field, the root length density, root area density, and biomass of fine roots were lower in female plantations than in male or mixed-sex plantations. Bacterial networks of female, male, and mixed-sex plantations were characterized by different composition of hub nodes, including connectors, modules, and network hubs. The sex composition of plantations altered bacterial and fungal community structures according to Bray-Curtis distances, with 44% and 65% of variance explained by the root biomass, respectively. The total soil nitrogen content of mixed-sex plantation was higher than that in female plantation in spring and summer. The mixed-sex plantation also had a higher β-1,4-N-acetyl-glucosaminidase activity in summer and a higher nitrification rate in autumn than the other two plantations. The seasonal soil N content, nitrification rate, and root distribution traits demonstrated spatiotemporal niche separation in the mixed-sex plantation. We argue that a strong female-female competition and limited nitrogen content could strongly impede plant growth and reduce the resistance of monosex plantations to climate change and the mixed-sex plantations constitutes a promising way to restore degraded land.

Effects of Voice Pitch on Social Perceptions Vary With Relational Mobility and Homicide Rate

Fundamental frequency ( fo) is the most perceptually salient vocal acoustic parameter, yet little is known about how its perceptual influence varies across societies. We examined how fo affects key social perceptions and how socioecological variables modulate these effects in 2,647 adult listeners sampled from 44 locations across 22 nations. Low male fo increased men’s perceptions of formidability and prestige, especially in societies with higher homicide rates and greater relational mobility in which male intrasexual competition may be more intense and rapid identification of high-status competitors may be exigent. High female fo increased women’s perceptions of flirtatiousness where relational mobility was lower and threats to mating relationships may be greater. These results indicate that the influence of fo on social perceptions depends on socioecological variables, including those related to competition for status and mates.

“Well, That’s What She Gets…”: Black Teenage Girls’ Sexual and Reproductive Choice in Young Adult Literature

Using Critical Discourse Analysis (CDA) this article explores the discourse around Black girl sexuality, teenage pregnancy, and teenage motherhood as depicted within Black authored young adult literature.

Role of Church Affiliation and the Sexual Behaviour Choices of Students in Selected Universities in Nairobi County, Kenya

Purpose: The current study sheds light on the role of church affiliation in shaping sexual attitudes and behaviour. Not enough was known about how Christianity can influence the construction of values and beliefs that discourage risky sexual behaviour among adolescents at universities in Kenya. Little was understood on the role of church affiliation explaining variation in adolescent sexuality among Christian communities at universities. Spirituality is an understudied subtype of religiosity yet it may explain patterns of sexual behaviour. Most studies that have examined the relationship between sexual behaviours and religiosity have focused on sexual intercourse. These studies have not examined other sexual behaviour choices, like internet sex.
 Methodology: Using a mixed-methods design, the relationship between church affiliation and sexual behaviour was examined. In quantitative analysis, a stratified probability sample of (n=176 students) who attend regular prayer sessions in three universities: the Kenyatta University (KU) Main Campus, the Jomo Kenyatta University of Agriculture and Technology (JKUAT) Karen Campus, and the Daystar University was used. Qualitative interviews were conducted with university administrators, chaplains, and other church workers. Undergirding the study was the social identity theory, which articulates the idea of people seeking to gain membership and acceptance in any social group.
 Findings: The findings suggest church affiliation has a significant effect on sexual attitudes, values, and behaviour. There seems to be an interaction between extrinsic and intrinsic religiosity, with frequent church attendance appearing to induce more conservative sexual beliefs, attitudes and behaviour. Church affiliation had a significant effect on sexual behaviour choices, which includes internet sex and cohabitation and extreme sexual activities.

‘You Never Thought about Me, Did You?’ Cloning and the Right to Reproductive Choice in Eva Hoffman’s The Secret (2001)

This article will critically appraise the extent to which new developments in the fields of reproductive technology are shown to impact female bodily autonomy and reproductive choice in Eva Hoffman’s novel The Secret. The Secret pushes its readers towards the more pressing and urgent questions arising from ongoing developments within the field of NRT and human cloning in a neoliberal climate. The novel cautions that, ultimately, the individual right to reproductive choice is never completely free; an awareness of external influences and a consideration of possible repercussions is integral to responsible decision-making in the context of NRT and cloning. However, the novel moves towards a possible reconceptualization of NRTs as part of the evolutionary progress of humankind. In returning to the body and biopolitical figurations, this article sees the novel’s protagonist, Iris, and her emergent cyborg identity as a manifestation of Haraway’s monstrous cyborg replete with possibility.

Divergent warning patterns influence male and female mating behaviours in a tropical butterfly.

Traits under divergent ecological selection that also function during mating can be important in maintaining species boundaries. Few studies have considered mutual mate choice, where both males and females base mating decisions on the same trait. Wing colouration in Heliconius butterflies evolved as a warning signal but also functions as a mating cue. We investigated the contribution of visual preference to assortative mating in an aposematic butterfly Heliconius cydno in the context of reproductive isolation with its sympatric, visually distinct relative Heliconius melpomene. Heliconius cydno have conspicuous white bands on their forewings, whereas those of H. melpomene are red in colour. We predicted that both sexes of H. cydno contributed to assortative mating by exhibiting visual preference towards conspecific wing colouration. We analysed published and new data from preference experiments, in which males were presented with conspecific and H. melpomene females. We also recorded female responses and mating outcomes in choice experiments, involving conspecific males with either the original white or artificially painted red forewing bands. Both sexes of H. cydno responded more positively towards the conspecific colouration, and males strongly preferred females of its own colours. In contrast, male colouration did not predict mating outcomes in female choice experiments. As courtships are initiated by males in butterflies, our findings suggest that female visual preference might be of secondary importance in H. cydno. Our data also suggest that the contribution of visual preference to reproductive isolation might be unequal between H. cydno and its sympatric relative H. melpomene.

Characterizing the schooling cycle

This paper examines the cyclical dynamics of school participation decision, using data for 16-24-year-olds attending full-time post-compulsory education in the UK in the period from 1995Q1 to 2019Q4. We find evidence of a highly persistent education cycle, largely explained by the business cycle. Importantly, the response of school participation to the business cycle is time-dependent – counter-cyclical in the period around the Great Financial Crisis and pro-cyclical in other years. We propose two channels as predictors of the cyclicality of schooling – the ability-to-pay for further education and the opportunity-cost of spending time in education rather than at work. We also show that the results are heterogeneous by gender, with female choices being more responsive to changes in aggregate macroeconomic conditions than male choices. Timely policy interventions using regular education as a counter-cyclical tool can help prevent persistent or permanent unemployment in the aftermath of a crisis.

Gender Biases Influencing Female Medical Students' Career Choice in Orthopaedics!

Madam, The choice of specialisation by medical students is influenced by a variety of factors, including the specialty's perceived credibility, parental influence, work-life balance, money, cultural background, rotations in the clinic, mentors' experiences, etc. In various medical professions gender disparity persists, in conventionally male-dominated specialties, despite rising numbers of women in medical schools and clinical practice regions globally. Inevitably, there were statistically substantial gender variations in the medical specialties chosen by male and female doctors, with the majority of men choosing surgery and orthopaedics.1

Influence of the human body odor compound HMHA on face perception.

Body odors convey information about the individuals, but the mechanisms are not fully understood yet. As far as human reproduction is concerned, molecules that are produced in sexually dimorphic amounts could be possible chemosignals. 3-hydroxy-3-methylhexanoic acid (HMHA) is one of them-more typical of men. Here, we investigated the possibility that the perception of gender and attractiveness in human faces could be implicitly influenced by this compound. Clearly feminine, ambiguous and clearly masculine faces were primed with an odor of HMHA, a control odor or air. Based on 100-ms face presentation, 40 raters had to identify the face's gender as quickly as possible and provide attractiveness evaluations. 3-hydroxy-3-methylhexanoic acid tended to be perceived as less pleasant and induced lower sniff duration in women compared with men. As to the effects of HMHA on face perception (vs. control conditions), we found that gender identification and the associated response time were unaffected by HMHA. Attractiveness of the faces, however, increased in presence of HMHA, but not in a sex-specific manner and only for unattractive faces with ambiguous gender. In sum, this study found no evidence in favor of a possible role of this sexually dimorphic compound in intrasexual competition nor in intersexual attraction.