Female Sexual Attractiveness Research Articles

Insulin-like peptide 8 (Ilp8) regulates female fecundity in flies.

Introduction: Insulin-like peptides (Ilps) play crucial roles in nearly all life stages of insects. Ilp8 is involved in developmental stability, stress resistance and female fecundity in several insect species, but the underlying mechanisms are not fully understood. Here we report the functional characterization of Ilp8s in three fly species, including Bactrocera dorsalis, Drosophila mercatorum and Drosophila melanogaster. Methods: Phylogenetic analyses were performed to identify and characterize insect Ilp8s. The amino acid sequences of fly Ilp8s were aligned and the three-dimensional structures of fly Ilp8s were constructed and compared. The tissue specific expression pattern of fly Ilp8s were examined by qRT-PCR. In Bactrocera dorsalis and Drosophila mercatorum, dsRNAs were injected into virgin females to inhibit the expression of Ilp8 and the impacts on female fecundity were examined. In Drosophila melanogaster, the female fecundity of Ilp8 loss-of-function mutant was compared with wild type control flies. The mutant fruit fly strain was also used for sexual behavioral analysis and transcriptomic analysis. Results: Orthologs of Ilp8s are found in major groups of insects except for the lepidopterans and coleopterans, and Ilp8s are found to be well separated from other Ilps in three fly species. The key motif and the predicted three-dimensional structure of fly Ilp8s are well conserved. Ilp8 are specifically expressed in the ovary and are essential for female fecundity in three fly species. Behavior analysis demonstrates that Ilp8 mutation impairs female sexual attractiveness in fruit fly, which results in decreased mating success and is likely the cause of fecundity reduction. Further transcriptomic analysis indicates that Ilp8 might influence metabolism, immune activity, oocyte development as well as hormone homeostasis to collectively regulate female fecundity in the fruit fly. Discussion: Our findings support a universal role of insect Ilp8 in female fecundity, and also provide novel clues for understanding the modes of action of Ilp8.

Micro‐climate correlations and conserved sexual dimorphism of cuticular hydrocarbons in European populations of the jewel wasp Nasonia vitripennis

1. Protection against desiccation and chemical communication are two fundamental functions of cuticular hydrocarbons (CHCs) in insects. In the parasitoid jewel wasp Nasonia vitripennis (Walker), characterised by a cosmopolitan distribution through largely different environments, CHCs function as universally recognised female sex pheromones. However, CHC uniformity as basis for sexual recognition may conflict with the desiccation protection function, expected to display considerable flexibility through adaptation to different environmental conditions.2. We compared male and female CHC profiles of N. vitripennis across a wide latitudinal gradient in Europe and correlated their CHC variation with climatic factors associated with desiccation. Additionally, we tested male mate discrimination behaviour between populations to detect potential variations in female sexual attractiveness.3. Results did not conform to the general expectation that longer, straight‐chain CHCs occur in higher proportions in warmer and drier climates. Instead, unexpected environmental correlations of intermediate chain‐length CHCs (C31) were found exclusively in females, potentially reflecting the different life histories of the sexes in N. vitripennis.4. Furthermore, we found no indication of population‐specific male mate preference, confirming the stability of female sexual attractiveness, likely conveyed through their CHC profiles. C31 mono‐ and C33 di‐methyl‐branched alkanes were consistently and most strongly associated with sexual dimorphism, suggesting their potential role in encoding the female‐specific sexual signalling function.5. Our study sheds light on how both adaptive flexibility and conserved sexual attractiveness can potentially be integrated and encoded in CHC profiles of N. vitripennis females across a wide distribution range in Europe.

Sex differences in sexual attraction for aesthetics, resources and personality across age.

Because sexual attraction is a key driver of human mate choice and reproduction, we descriptively assess relative sex differences in the level of attraction individuals expect in the aesthetic, resource, and personality characteristics of potential mates. As a novelty we explore how male and female sexual attractiveness preference changes across age, using a dataset comprising online survey data for over 7,000 respondents across a broad age distribution of individuals between 18 and 65 years. In general, we find that both males and females show similar distribution patterns in their preference responses, with statistically significant sex differences within most of the traits. On average, females rate age, education, intelligence, income, trust, and emotional connection around 9 to 14 points higher than males on our 0-100 scale range. Our relative importance analysis shows greater male priority for attractiveness and physical build, compared to females, relative to all other traits. Using multiple regression analysis, we find a consistent statistical sex difference (males relative to females) that decreases linearly with age for aesthetics, while the opposite is true for resources and personality, with females exhibiting a stronger relative preference, particularly in the younger aged cohort. Exploring non-linearity in sex difference with contour plots for intelligence and attractiveness across age (mediated by age) indicates that sex differences in attractiveness preferences are driven by the male cohort (particularly age 30 to 40) for those who care about the importance of age, while intelligence is driven by females caring relatively more about intelligence for those who see age as very important (age cohort 40 to 55). Overall, many of our results indicate distinct variations within sex at key life stages, which is consistent with theories of selection pressure. Moreover, results also align with theories of parental investment, the gender similarities hypothesis, and mutual mate choice-which speaks to the fact that the broader discipline of evolutionary mate choice research in humans still contains considerable scope for further inquiry towards a unified theory, particularly when exploring sex-difference across age.

The Measurement of Female Early Adolescent Sexual Desire

ABSTRACT We used the developmental systems model to deduce a definition of female early adolescent sexual desire. We evaluated a measure of this phenomenon with a secondary analysis of data from a randomized group sexual health intervention trial involving low-income, English-speaking, seventh grade Latinas enrolled in a Miami-Dade County public school (n = 542). As part of this study, girls completed a four-item early adolescent sexual desire (EASD) measure. Study findings supported internal consistency (Cronbach’s alpha = .81 to .82) and stability over a 1-month period (r = .74). Developmental sensitivity was supported by a decline in stability over 12- (r = .66) and 24-month periods (r = .56). Validity was supported by correlations with puberty changes, sexual intentions, sexting, and sexual behavior, and hypothesized mean differences associated with dating and preference for shoes culturally associated with female sexual attractiveness (p < .01). Research implications include validation work with other ethnic/racial groups and using the EASD as a starting point for a measurement continuum tracking development of sexual desire across adolescence and into adulthood. Directions for future research also include measuring the development of sexual desire in boys and transgendered youth across adolescence and into adulthood.

Female Voice-Related Sexual Attractiveness to Males: Does it Vary With Different Degrees of Conception Likelihood?

Previous investigations have found that female voice-related attractiveness to males increases when both conception likelihood (CL) and voice fundamental frequency (fo) are elevated. To test this hypothesis, we conducted a perceptual experiment where 78 heterosexual males rated sexual attractiveness of 9 female voice samples, recorded at menstrual, follicular and luteal phases of the menstrual cycle under two double-blinded randomly allocated conditions: a natural menstrual cycle (placebo condition) and when using an oral contraceptive pill (OCP condition). The voice samples yielded a total of 54 stimuli that were visually sorted and rated using Visor software. Concentrations of estrogens, progesterone and testosterone were analyzed, and measurements of speaking fundamental frequency (sfo) and its standard deviation (sfoSD), fo derivative (dfo) and fo slope were made. A multilevel ordinal logistic regression model nested in listeners and in females, and adjusted by phase and condition, was carried out to assess the association between ratings and: (1) phases and conditions; (2) sex steroid hormonal concentrations; and (3) voice parameters. A high probability of obtaining high ratings of voice sexual attractiveness was found for: (1) menstrual phase of placebo use and follicular phase of OCP use; (2) for low estradiol to progesterone ratio and testosterone concentrations; and (3) for low dfo. The latter showed a moderate statistical association with ratings of high attractiveness, as compared with the small association found for the remaining variables. It seems that the voice is a weak cue for female CL. Female sexual attraction to males may be a consequence of what females do in order to regulate their extended sexuality across the menstrual cycle rather than of estrus cues, the use of paralinguistic speech patterns being an example.

Female sexual attractiveness and sex recognition in leopard gecko: Males are indiscriminate courters

The nature and hormonal control of cues used for recognition of sex and reproductive status of conspecifics remain largely unstudied in reptiles. It has been proposed that production of a female attractiveness pheromone controlled by female ovarian hormones (and which is suppressed by male gonadal androgens) is necessary to elicit courtship in males. In the case of leopard gecko (Eublepharis macularius), it has been suggested that an individual is recognized as a male and attacked unless it produces female-specific stimuli in its skin and that females are attacked, not courted, while shedding. We tested the reactions of males to control males and control shedding and non-shedding females, castrated males, females treated with exogenous androgens (testosterone and dihydrotestosterone), and prepubertal individuals. The individuals with high androgen levels (i.e., control males and hormone-treated females) were attacked while animals in all the other groups were courted. Our results indicate that in leopard gecko hormonally controlled pheromones advertising female attractiveness are not required and that sex discrimination is based on the presence or absence of cues dependent on masculinization by male gonadal steroids.

Insulin signaling in female Drosophila links diet and sexual attractiveness.

Appropriate sexual selection or individual sexual attractiveness is closely associated with the reproductive success of a species. Here, we report that young male flies exhibit innate courtship preference for female flies that are raised on higher-yeast diets and that have greater body weight and fecundity, but reduced locomotor activity and shortened lifespan. Male flies discriminate among females that have been fed diets that contain 3 different yeast concentrations-1, 5, and 20% yeast- via gustatory, but not visual or olfactory, perception. Female flies that are raised on higher-yeast diets exhibit elevated expression levels of Drosophila insulin-like peptides (di lps), and we demonstrate that hypomorphic mutations of di lp2, 3, 5 or foxo, as well as oenocyte-specific gene disruption of the insulin receptor, all abolish this male courtship preference for high yeast-fed females. Moreover, our data demonstrate that disrupted di lp signaling can alter the expression profile of some cuticular hydrocarbons (CHCs) in female flies, and that genetic inhibition of an enzyme involved in the biosynthesis of CHCs in oenocytes, elongase F, also eliminates the male courtship preference. Together, our findings provide mechanistic insights that link female reproductive potential to sexual attractiveness, thereby encouraging adaptive mating and optimal reproductive success.-Lin, W.-S., Yeh, S.-R., Fan, S.-Z., Chen, L.-Y., Yen, J.-H., Fu, T.-F., Wu, M.-S., Wang, P.-Y. Insulin signaling in female Drosophila links diet and sexual attractiveness.

Tissue-specific insulin signaling mediates female sexual attractiveness.

Individuals choose their mates so as to maximize reproductive success, and one important component of this choice is assessment of traits reflecting mate quality. Little is known about why specific traits are used for mate quality assessment nor about how they reflect it. We have previously shown that global manipulation of insulin signaling, a nutrient-sensing pathway governing investment in survival versus reproduction, affects female sexual attractiveness in the fruit fly, Drosophila melanogaster. Here we demonstrate that these effects on attractiveness derive from insulin signaling in the fat body and ovarian follicle cells, whose signals are integrated by pheromone-producing cells called oenocytes. Functional ovaries were required for global insulin signaling effects on attractiveness, and manipulations of insulin signaling specifically in late follicle cells recapitulated effects of global manipulations. Interestingly, modulation of insulin signaling in the fat body produced opposite effects on attractiveness, suggesting a competitive relationship with the ovary. Furthermore, all investigated tissue-specific insulin signaling manipulations that changed attractiveness also changed fecundity in the corresponding direction, pointing to insulin pathway activity as a reliable link between fecundity and attractiveness cues. The cues themselves, cuticular hydrocarbons, responded distinctly to fat body and follicle cell manipulations, indicating independent readouts of the pathway activity from these two tissues. Thus, here we describe a system in which female attractiveness results from an apparent connection between attractiveness cues and an organismal state of high fecundity, both of which are created by lowered insulin signaling in the fat body and increased insulin signaling in late follicle cells.

Using whole-group metabolic rate and behaviour to assess the energetics of courtship in red-sided garter snakes

Reproductive effort is an important aspect of life history as reproductive success is arguably the most important component of fitness. Males tend to compete for access to females and, in the process, expend their energetic capital on mate searching, male–male competition and courtship rather than directly on offspring. Red-sided garter snakes, Thamnophis sirtalis parietalis , are an exceptional model for studying energetic costs of courtship and mating as they fast during the spring mating season, which segregates the cost of energy acquisition from the cost of courtship and mating. However, measuring an individual male's metabolic rate during courtship is complicated by the fact that male courtship behaviour in red-sided garter snakes is dependent on both the detection of a female sexual attractiveness pheromone and on facilitated courtship (i.e. vigorous courtship is only exhibited in the presence of other males). Thus, traditional techniques of placing a mask over the head of individuals would prevent male courtship behaviour, and single animals placed in a flow-through chamber would not yield ecologically realistic levels of courtship, which are only seen in the context of a mating aggregation in this species. Because of these difficulties, we placed groups of males in a flow-through metabolic chamber together with a single female whose respiratory gases were vented outside the chamber to yield a whole-group metabolic rate during competitive courtship. We also measured the standard metabolic rates (SMR) of the males individually for comparison with active metabolic rates. Conservative estimates of peak group metabolic rates during courtship are 10–20 times higher than resting group metabolic rate, which was 1.88 times higher than SMR. These measurements, coupled with the fact that these males are aphagous during the breeding, indicates that costs of courtship may be high for males and has implications for the male mating tactics in this system.

Imorin: a sexual attractiveness pheromone in female red-bellied newts (Cynops pyrrhogaster)

The male red-bellied newt (Cynops pyrrhogaster) approaches the female’s cloaca prior to performing any courtship behaviour, as if he is using some released substance to gauge whether she is sexually receptive. Therefore, we investigated whether such a female sexual attractiveness pheromone exists. We found that a tripeptide with amino acid sequence Ala-Glu-Phe is secreted by the ciliary cells in the epithelium of the proximal portion of the oviduct of sexually developed newts and confirmed that this is the major active substance in water in which sexually developed female newts have been kept. This substance only attracted sexually developed male newts and acted by stimulating the vomeronasal epithelial cells. This is the first female sexual attractiveness peptide pheromone to be identified in a vertebrate.

Chemosignalling effects of human tears revisited: Does exposure to female tears decrease males’ perception of female sexual attractiveness?

ABSTRACTGelstein et al. reported the results of three experiments suggesting a dampening influence of inhalation of female emotional tears on males’ arousal and perception of female sexual attractiveness, specifically in non-sexual situations. This prompted the hypothesis that crying exerts its influence on others not only via the auditory and visual mode but also via chemosignals. In three studies, we attempted to replicate and extend Gelstein et al.’s findings by including an additional condition with irritant tears, by using pictures of sexually attractive women, and by testing related hypotheses on the pro-social effects of exposure to tears. All three studies, separately or combined in a meta-analysis, failed to replicate the original inhibitory effects of tears. In addition, sniffing tears did not affect measures of connectedness, aggression and pro-social behaviour. It is concluded that the effects of female tears on male arousal and perception of female sexual attractiveness, if any, are very weak at best. Rather, it seems that crying exerts its strong inter-personal effects through the visual and auditory sensory channels.

Red-colored products enhance the attractiveness of women

This research investigated whether carrying red-colored products enhances female sexual attractiveness. In the first experiment, male participants were instructed to observe women carrying laptops in different colors (black, silver, red, or blue). The results indicated that the women who carried red laptops were perceived to possess a significantly higher level of attractiveness and sex appeal than those who carried laptops in other colors; however, the red laptop did not affect men’s perceptions of the assertiveness and health level of the women. In the second experiment, the initial experiment was repeated but female participants observed the women; laptop color did not influence how the participants perceived the women’s attractiveness, sex appeal, assertiveness, and level of health. In other words, women carrying products in red only affected how men, but not women, perceived them; thus, women using red products are more attractive and sexually appealing to men.

A glimpse into the sexual biology of the “zygiellid” spider genus Leviellus

Abstract We investigated the mating biology of the previously unstudied central European spider Leviellus thorelli (Ausserer 1871) by staging laboratory mating trials using males and females of varying mating histories. Our aim was to seek common themes in sexual behaviors of the sexually size-monomorphic “zygiellid” spiders with their putatively close relatives, araneids and nephilids, which are relatively well studied with respect to sexual biology. We found L. thorelli mating biology to more closely resemble that of sexually size-monomorphic araneids than that of dimorphic nephilids. Unlike in nephilids with sexually conflicted adaptations, we found no evidence for genital damage or plugging in Leviellus Wunderlich 2004, although we found rare cases of half-eunuchs. We suggest that the mating system of L. thorelli spiders is determined by short female sexual attractiveness, reduced receptivity after mating and/or intensive mate guarding.

O07.3 A Psychological Experiment to Examine the Global Impact of Stigma on Individuals Diagnosed with Type 1 Herpes Simplex Virus (HSV-1)

BackgroundHSV-1 causes at least 50% of primary genital herpes infections in Europe, Canada, Australia and the USA. In the UK, rates may be even higher, as the level 3 STI...

Pheromonal control of the invasive brown treesnake: potency of female sexual attractiveness pheromone varies with ovarian state

The female sex pheromone has potential a s a control tool for the Brown Treesnake, Boiga irregularis Merrem, a pest introduced into Guam. We conducted male-guided bioassays to determine whether potency of the female pheromone varied according to reproductive state and during vitellogenesis. In weekly simultaneous choice tests, we presented males with skin lipid samples from vitellogenic females, non-vitellogenic females, conspecific males, and carrier controls. The total time each sample was tongue-flicked was recorded: mean total tongue-flick time was highest for samples from vitellogenic females followed by samples from non-vitellogenic females. Pair-wise comparisons of male tongue-flick time for samples of non-vitellogenic females versus males and vitellogenic females versus non-vitellogenic females revealed differences in some weeks, but the greatest and most frequent differences were between vitellogenic females versus males. We observed no trend in the potency of the pheromone during vitellogenesis. Pheromone potency was greatest during vitellogenesis, with lesser potency retained while non-reproductive. Efforts at chemical identification of the pheromone and development of control tools should focus on material obtained from vitellogenic females.

Effects of forced copulations on female sexual attractiveness in fruit flies

Male fruit flies (Drosophila melanogaster) force-copulate with females during the females' short vulnerable period following eclosion. Although sexually immature at that time, the females produce viable progeny from forced copulations. While the females could gain fitness from remating with their chosen male when reaching sexual maturity, mating in female fruit flies is typically followed by a long period of reduced attractiveness and receptivity. To test whether forcibly mated females can overcome the typical effects of mating, we quantified the effects of consensual versus forced matings on female attractiveness and receptivity. Forcibly mated females were as attractive to males as same-age virgin females and more attractive than consensually mated females. The forcibly mated females, however, remated at lower frequencies than same-age virgin females but at higher frequencies than consensually mated females. Our results suggest an intriguing outcome of sexual conflict in which males can sire offspring with and reduce the receptivity of forcibly mated females, but these females can retain their attractiveness and partial receptivity to males.

Sexual receptivity varies according to female age in a Neotropical nuptial gift-giving spider

Abstract For many spiders, sex pheromones associated with female silk are important stimuli that elicit male searching and courtship behaviors. In that context, female sexual receptivity and chemical attractiveness can depend on age and reproductive status. In Paratrechalea ornata (Mello-Leitao 1943) (Araneae: Trechaleidae), males offer females a nuptial gift (a prey wrapped in silk) during courtship. Gift construction is elicited by the presence of female silk, and silk attractiveness is influenced by female age, increasing from 20 days after the female reaches adulthood. Our goal was to investigate whether female age affects female sexual receptivity and to discuss the relationship between receptivity and silk attractiveness. We exposed 26 virgin females, from 2 to 28 days after the final molt, to males offering a nuptial gift. Female sexual receptivity was age dependent and increased with adult female age. Females over 15 days from adulthood accepted more gifts than younger females, but the latency of ...

Pheromonal Mediation of Intraseasonal Declines in the Attractivity of Female Red-Sided Garter Snakes, Thamnophis sirtalis parietalis

During the breeding season, female red-sided garter snakes (Thamnophis sirtalis parietalis) produce and express a sexual attractiveness pheromone that elicits male courtship behavior. Composed of a homologous series of saturated and monounsaturated methyl ketones, this pheromone is expressed in female skin lipids. Recent studies have shown that the sexual attractivity of unmated female garter snakes declines as the breeding season progresses. Here, we investigated whether temporal changes in the quantity and/or quality of the female sexual attractiveness pheromone are responsible for the observed loss of attractivity. Female red-sided garter snakes were collected immediately following spring emergence and held under natural conditions for the duration of the breeding season. Behavioral experiments confirmed that unmated females become significantly less attractive to males within two weeks of emergence from hibernation. Additionally, these females had lower estradiol concentrations at two weeks post-emergence. Subsequent chemical analyses revealed qualitative variation between the pheromone profiles of newly emerged females and those of females at two weeks post-emergence. Together, these results support the hypothesis that changes in the female sexual attractiveness pheromone are responsible for declining post-emergence female attractivity in garter snakes.

Sexual Cues Emanating From the Anchorette Chair: Implications for Perceived Professionalism, Fitness for Beat, and Memory for News

The experimental study reported here employed one of the most compelling visual cues of female sexual attractiveness (low waist-to-hip ratio) to test the influence of news anchor sexualization on audience evaluations of her as a professional and their memory for the news that she presents. Male participants saw the sexualized version of the anchor as less suited for war and political reporting. They also encoded less news information presented by the sexualized than her unsexualized version. Conclusions were drawn in line with evolutionary psychology expectations of men’s cognitive susceptibility to visual sex cues. Women participants, on the other hand, did not vary across conditions in their assessments of the anchor’s competence to report on war and political news. Moreover, they encoded more news information presented by the sexualized than unsexualized anchor condition.

Low Temperature Dormancy Affects the Quantity and Quality of the Female Sexual Attractiveness Pheromone in Red-sided Garter Snakes

Low temperature dormancy is a necessary requirement of the annual cycle of most nonmigratory, temperate vertebrates. The red-sided garter snake, Thamnophis sirtalis parietalis, overwinters in communal dens during its prolonged winter dormancy (8 mo), and upon emergence, reproductive behavior of both sexes is maximal. Previous work on this species showed that male courtship behavior is maximally induced after simulated low temperature dormancy. The purpose of this study was to determine whether low temperature dormancy affects the pheromone profiles of individual female red-sided garter snakes. We collected females in the fall at den sites in Manitoba, Canada, and extracted pheromones from individuals at three different time points: fall (field), winter (lab), and spring (lab). Total skin lipid and pheromone fraction masses increased from fall to spring, and pheromone profiles were distinctly different in the fall and spring. Pheromone profiles became dominated by the long-chain, unsaturated methyl ketone components of the blend by the time snakes emerged in the spring. Further, the amounts of both saturated and unsaturated components increased from fall to spring, suggesting significant sex pheromone synthesis was induced by low temperature dormancy.