Sexual segregation in western grey kangaroos: testing alternative evolutionary hypotheses

In sexually dimorphic ungulates, sexual segregation is hypothesized to have evolved because of sex-specific differences in body size and/or reproductive strategies. We tested these alternative hypotheses in kangaroos, which are ecological analogues of ungulates. Kangaroos exhibit a wide range of body sizes, particularly among mature males, and so the effects of body size and sex can be distinguished. We tested predictions derived from these hypotheses by comparing the distribution of three sex–sex size classes of western grey kangaroos Macropus fuliginosus, in different habitats, and the composition of groups of kangaroos, across seasons. In accordance with the predation risk-reproductive strategy hypothesis, during the non-breeding season, females, which were more susceptible to predation than larger males, and were accompanied by vulnerable young-at-foot, were over-represented in secure habitats. Large males, which were essentially immune to predation, occurred more often than expected in nutrient-rich habitat, and small males, which faced competing demands of predator avoidance and feeding, were intermediate between females and large males in their distribution across habitats. During the breeding season, females continued to be over-represented in secure habitats when their newly emerged pouch young were most vulnerable to predation. All males occupied these same habitats to maximize their chances of securing mates. Consistent with the social hypotheses, groups composed of individuals of the same sex, irrespective of body size, were over-represented in the population during the non-breeding season, while during the breeding season all males sought females so that mixed-sex groups predominated. These results indicate that body size and reproductive strategies are both important, yet independent, factors influencing segregation in western grey kangaroos.

Effect of deer velvet on sexual function in men and their partners: a double-blind, placebo-controlled study

The use of alternative medicines and herbal remedies is an increasing trend in Western societies. For years, people have taken products made of deer velvet for their alleged beneficial effects on sexual function. There has been no scientific investigation of the effects of deer velvet powder on the sexual functioning of human males. This study investigated sexual function in men during a 12-week double-blind, placebo-controlled trial of deer velvet. Thirty-two volunteer male participants, aged 45–65 years, and their partners, were randomly assigned to either the deer velvet or placebo study group. The males took capsules containing ground deer velvet or placebo everyday for 12 weeks. Two sexual function questionnaires (the International Index of Erectile Function and the Brief Index of Sexual Function for Women) used at pre- and posttreatment assessed changes in sexual functioning in males and their partners. Blood tests at baseline, and end of study, determined levels of sex-related hormones in male participants. There were no significant differences in the sexual behavior of the men taking deer velvet compared with the men taking placebo capsules. There were no significant hormone changes from baseline to the end of the study in either group of men. We conclude that in normal males there was no advantage in taking deer velvet to enhance sexual function. All alternative health products or nutritional supplements should be subjected to randomized placebo-controlled trials to determine efficacy.

Are aspects of study design associated with the reported prevalence of female sexual difficulties?

Objective: To investigate associations between the prevalence of sexual  difficulties reported in published studies and design features of those studies to determine if differences in design contribute to variation in prevalence estimates.
Design: Systematic review, multivariate analysis.
Setting: Studies published internationally in English.
Patient(s): Not applicable.
Intervention(s): None.
Main Outcome Measure(s): Prevalence estimates of difficulty with desire, arousal, orgasm, and sexual pain reported in published studies.
Result(s): Our systematic literature search identified 1,380 publications. Fifty-five studies met our inclusion criteria (reporting prevalence, sample size and response rate, sample size greater than 100, not clinic based). Reported prevalence of sexual difficulty varied across studies (up to tenfold). Eleven aspects of research conduct in these studies were included in our multivariate analysis as explanatory variables. Five aspects of study design and conduct (data collection procedures, inclusion criteria, duration of sexual difficulty recorded, sample size, and response rate) were associated with the reported prevalence of at least one type of sexual difficulty independently of likely predictors of true variation in prevalence: study location, study year, and age range of participants.
Conclusion(s): This review provides evidence that study design may influence reported prevalence estimates of female sexual difficulties and contribute to the wide variation in published estimates.

What is the "true" prevalence of female sexual dysfunctions and does the way we assess these conditions have an impact?

Introduction. A wide range of prevalence estimates of female sexual dysfunctions (FSD) have been reported.
Aim. Compare instruments used to assess FSD to determine if differences between instruments contribute to variation in reported prevalence.
Main Outcome Measures. Sexual Function Questionnaire combined with Female Sexual Distress Scale (SFQ-FSDS) was our gold standard, validated instrument for assessing FSD. Alternatives were SFQ alone and two sets of simple questions adapted from Laumann et al. 1994.
Methods. A postal survey was administered to a random sample of 356 Australian women aged 20 to 70 years.
Results. When assessed by SFQ-FSDS, prevalence estimates (95% confidence intervals) of hypoactive sexual desire disorder, sexual arousal disorder (lubrication), orgasmic disorder, and dyspareunia were 16% (12% to 20%), 7% (5% to 11%), 8% (6% to 12%), and 1% (0.5% to 3%), respectively. Prevalence estimates varied across alternative instruments for these disorders: 32% to 58%, 16% to 32%, 16% to 33%, and 3% to 23%, respectively. Compared with SFQ-FSDS alternative instruments produced higher estimates of desire, arousal and orgasm disorders and displayed a range of sensitivities (0.25 to 1.0), specificities (0.48 to 0.99), positive predictive values (0.01 to 0.56), and negative predictive values (0.95 to 1.0) across the disorders investigated. Kappa statistics comparing SFQ-FSDS and alternative instruments ranged from 0 to 0.71 but were predominantly 0.44 or less. Changing recall from previous month to 1 month or more in the previous year produced higher estimates for all disorders investigated. Including sexual distress produced lower estimates for desire, arousal, and orgasm disorders.
Conclusions. Prevalence estimates of FSD varied substantially across instruments. Relatively low positive predictive values and kappa statistics combined with a broad range of sensitivities and specificities indicated that different instruments identified different subgroups. Consequently, the instruments researchers choose when assessing FSD may affect prevalence estimates and risk factors they report.

Plumage reflectance and the objective assessment of avian sexual dichromatism

Assessment of color using human vision (or standards based thereon) is central to tests of many evolutionary hypotheses. Yet fundamental differences in color Vision between humans and other animals call this approach into question. Here we use techniques for objectively assessing color patterns that avoid reliance on species-specific (e.g., human) perception. Reflectance spectra are the invariant features that we expect the animal's color cognition to have evolved to extract. We performed multivariate analyses on principal components derived from >2,600 reflectance spectra (300-720 nm) sampled in a stratified random design from different body regions of male and female starlings in breeding plumage. Starlings possess spatially complex plumage patterns and extensive areas of iridescence. Our study revealed previously unnoticed sex differences in plumage coloration and the nature of iridescent and noniridescent sex differences. Sex differences occurred in some body regions bur not others, were more pronounced at some wavelengths (both ultraviolet and human visible), and involved differences in mean reflectance and spectral shape. Discriminant analysis based on principal components were sufficient to sex correctly 100% of our sample. If hidden sexual dichromatism is widespread, then it has important implications for classifications of animals as mono- or dimorphic and for taxonomic and conservation purposes.

Environmental variation and the maintenance of polymorphism : the effect of ambient light spectrum on mating behaviour and sexual selection in guppies

The intensity of sexual selection is influenced by environmental conditions because these conditions influence signal propagation and the risks of the signal being exploited by predators and parasites. We explore the possibility that spatial or temporal heterogeneity in environmental signalling conditions (in this case light spectrum) may induce fluctuating sexual selection on male behaviour and ornamentation in guppies. We used shade cloth and filters to experimentally manipulate light spectrum, mimicking conditions found naturally: early morning/late afternoon light (SC treatment), midday forest shade (F89 filter treatment) and midday woodland shade (F55 filter treatment). Females were more responsive to male courtship and males were less likely to attempt sneak copulations under F55 light than the other two treatments. By contrast, male display rate was not influenced by treatment. Females tended to prefer the same males under SC and F55 light, but attractiveness in these treatments was unrelated to attractiveness under F89 light. There were similarities among treatments in the traits that females preferred: females preferred males with larger areas of orange in all three treatments. There were, however, also some differences, including preference for larger males under F89 light and for smaller males under the other treatments. Overall, the influence of ambient light spectrum on the relative importance of mate choice and male sneak copulation may have important implications for the mode and strength of sexual selection in different environments. The findings on attractiveness and preference functions, however, suggest that light spectrum only weakly affects the direction of sexual selection by female choice.

Clinical and demographic differences between sexually violent predators and other commitment types in a state forensic hospital

Sexual offenders who are involuntarily civilly committed to a secure state hospital as Sexually Violent Predators (SVPs) appear to differ significantly from other current patient populations. Demographically, SVPs are older and more predominantly Caucasian than other patients. They are less frequently psychotic than patients committed under other state statutes such as those found incompetent to stand trial, not guilty by reason of insanity and mentally ill prison transfers. Another salient dimension which distinguishes SVPs is the degree of psychopathy observed in these patients. As a group, SVPs display only slightly higher levels of psychopathy than other patient groups as measured by the revised Psychopathy Checklist. Yet when considered by offender type, rapists are found to have significantly higher average psychopathy scores than other patients, while child molesters are assessed as having lower average psychopathy scores than most other patient commitment categories.

Professional response and attitudes toward female-perpetrated child sexual abuse : a study of psychologists, probationary psychologists and child protection workers

Previous studies have suggested that lay people and professionals both tend to deny or minimise female-perpetrated sexual abuse of children. However, such abuse has been shown to have negative impacts on the victims. This study investigated whether professionals who might work with victims or perpetrators of childhood sexual abuse show a bias in processing scenarios and making decisions when confronted such abuse. A sample of 231 psychiatrists, psychologists, probationary psychologists and child protection workers responded to variations in vignettes in which women and men offended against children, and completed a questionnaire assessing attitudes to women's sexually abusive/offending behaviour toward children. All professional groups regarded cases involving female perpetrators of child sexual abuse as serious and deserving of professional attention. However, while there were some differences between groups, female perpetrators were more likely than male perpetrators to be considered leniently, suggesting that minimisation of female-perpetrated sexual abuse of children may persist in the professional arena. As a result, both female perpetrators of sexual abuse and their victims may go untreated, and in the case of perpetrators, their behaviour may go unsanctioned. Training for professionals to enhance their understanding of the seriousness of sexual abuse perpetrated by women is indicated.

Sexual and relationship satisfaction among heterosexual men and women : the importance of desired frequency of sex

Little is known of the extent to which heterosexual couples are satisfied with their current frequency of sex and the degree to which this predicts overall sexual and relationship satisfaction. A population-based survey of 4,290 men and 4,366 women was conducted among Australians aged 16 to 64 years from a range of sociodemographic backgrounds, of whom 3,240 men and 3,304 women were in regular heterosexual relationships. Only 46% of men and 58% of women were satisfied with their current frequency of sex. Dissatisfied men were overwhelmingly likely to desire sex more frequently; among dissatisfied women, only two thirds wanted sex more frequently. Age was a significant factor but only for men, with those aged 35-44 years tending to be least satisfied. Men and women who were dissatisfied with their frequency of sex were also more likely to express overall lower sexual and relationship satisfaction. The authors' findings not only highlight desired frequency of sex as a major factor in satisfaction, but also reveal important gender and other sociodemographic differences that need to be taken into account by researchers and therapists seeking to understand and improve sexual and relationship satisfaction among heterosexual couples. Other issues such as length of time spent having sex and practices engaged in may also be relevant, particularly for women.

What's in a measure? A multi-method study of child sexual offenders' beliefs

The hypothesis that child sexual offenders (CSOs) hold distorted, offence-supportive beliefs is usually investigated using interview and questionnaire techniques. However, in light of various problems associated with the use of these techniques, researchers are increasingly turning to cognitive-experimental approaches. To date, no study has examined potential differences in the nature of the beliefs that are revealed using interview, questionnaire, and experimental methods. In this study, data is gathered using these three methods and the results triangulated. CSOs are interviewed and the content categorised into five belief types. CSOs and offender controls then complete a questionnaire measure of offence-supportive beliefs and an experimental task (Rapid Serial Visual Presentation-Modified, or RSVP-M), which uses sentence reading times to explore content held in cognitive structures. As hypothesised, CSOs showed evidence of holding distorted beliefs according to the interview and questionnaire measures. Against predictions, however, CSOs did not show evidence of holding distorted belief structures on the RSVP-M task. In fact, the three methods showed no agreement regarding the belief types each CSO was deemed to hold. These results raise important questions about the phenomena and potential artefacts measured by each method.

A pilot randomized, double-blind, placebo-controlled study of granisetron in the treatment of sexual dysfunction in women associated with antidepressant use

A pilot study was conducted to evaluate the usefulness of granisetron for the treatment of antidepressant induced sexual dysfunction in women. Twelve women with antidepressant induced sexual dysfunction (AISD) were assigned granisetron (n=5) or placebo (n=7) in a 14-day randomized, double-blind, placebo-controlled study. One participant in the granisetron group did not complete the study. Participants were assessed at baseline, day 7 and day 14 using the Feiger Sexual Function and Satisfaction Questionnaire and the Arizona Sexual Experience Scale. No statistical differences were measured at baseline or at endpoint between the granisetron or placebo group. This study did not produce evidence supporting the usefulness of granisetron in AISD.

Association between sexual behavior and cervical cancer screening

Background: Not much is known about whether women who follow Pap testing recommendations report the same pattern of sexual behavior as women who do not.
Methods: Data come from part of a larger population-based computer-assisted telephone survey of 8656 Australians aged 16–64 years resident in Australian households with a fixed telephone line (Australian Longitudinal Study of Health and Relationships [ALSHR]). The main outcome measure in the current study was having had a Pap test in the past 2 years.
Results: Data on a weighted sample of 4052 women who reported sexual experience (ever had vaginal intercourse) were analyzed. Overall, 73% of women in the sample reported having a Pap test in the past 2 years. Variables individually associated with Pap testing behavior included age, education, occupation, cohabitation status, residential location, tobacco and alcohol use, body mass index (BMI), lifetime and recent number of opposite sex partners, sexually transmitted infection (STI) history, and condom reliance for contraception. In adjusted analyses, women in their 30s, those who lived with their partner, and nonsmokers were more likely to have had a recent Pap test. Those who drank alcohol at least weekly were more likely to have had a recent test than irregular drinkers or nondrinkers. Women with no sexual partners in the last year were less likely to have had a Pap test, and women who reported a previous STI diagnosis were more likely to have had a Pap test in the past 2 years.
Conclusions: There are differences in Pap testing behavior among Australian women related to factors that may affect their risk of developing cervical abnormalities. Younger women and regular smokers were less likely to report a recent test. Screening programs should consider the need to focus recruitment strategies for these women.

Life histories of the Insectivora : the role of phylogeny, metabolism and sex differences

Life-history data for 63 species from the mammalian order Insectivora have been collated from the literature. These data were analysed for covariation and for correlations with body mass, brain mass and mass-specific resting metabolic rate. An independent contrasts method has been used to remove the effect of phylogeny. Due to uncertainties surrounding their evolutionary relationships, 22 different phylogenies of insectivores have been used as a basis for comparative analysis. The results show that several key correlations between life-history variables are only significant when certain phylogenies are used, highlighting the problems of such analyses when the phylogeny used is inaccurate. After removing the effect of phylogeny, relatively few significant correlations remain. Insectivores that have a high body mass have relatively lower metabolic rates, longer lifespans and longer gestation lengths. There is some support for a fast±slow continuum in insectivore life-history evolution: there are some significant positive correlations between measures of growth rates (e.g. gestation length and age at weaning) and lifespan, and some negative correlations between growth rates and measures of reproductive output. It is suggested that the seasonality of life of many insectivores may have played an influential role in the evolution of the group, in particular in delaying the onset of sexual maturity. There is little indication that brain size influences life-history evolution in this order, but metabolism may play an important role. The energetic requirements of maintaining high metabolic rates in small mammals such as insectivores may be constraining life histories to a greater extent than occurs in larger mammals. This effect may have obscured the relationship between metabolic rate and life histories in wider inter-order analyses. Finally, there is considerable evidence that sex differences play a large role in shaping insectivore evolution, and it is suggested that this factor must be considered more often in future studies of mammalian life histories in general.

Reversed sexual dimorphism and altered prey base : the effect on sooty owl (Tyto tenebricosa tenebricosa) diet

The ecology and function of many Australian predators has likely been disrupted following major changes in prey base due to declines in distribution and abundance of small mammals following European settlement. This study investigated various aspects of the dietary ecology of sooty owls (Tyto tenebricosa tenebricosa), including sexual variation as they potentially exhibit the greatest degree of reversed sexual dimorphism of any owl species worldwide. Sooty owls are highly opportunistic predators of non-volant small mammals, consuming most species known to exist in the region, so their diet fluctuates seasonally and spatially due to varying prey availability, and is particularly influenced by the breeding cycles of prey. Significant intersexual dietary differences existed with female sooty owls predominantly consuming much larger prey items than males, with dietary overlap at 0.62. The current reliance on relatively few native mammalian species is of conservation concern, especially when mammal declines are unlikely to have ceased as many threatening processes still persist in the landscape. Sooty owl conservation appears inextricably linked with small mammal conservation. Conservation efforts should be focussed towards improving prey densities and prey habitat, primarily by implementing control programs for feral predators and preventing the loss of hollow-bearing trees throughout the landscape

At what age can females consent to sexual activity? A survey of jury-eligible Australians

One suggested reason for the low conviction rates of alleged child sexual abuse offenders relates to the attitudes and beliefs the public hold about such victims; sexual interactions starting at an earlier age; and because the oversexualisation of children and teenagers portrayed in the media may have affected perceptions as to when females are capable ofgiving consent to sexual interactions. A sample of 580 jury-eligible participants completed six implicit questions via an online survey regarding females' capacity to consent. While participants had similar perceptions in response to the type of question asked, there were some differences due to respondent group. When significant differences were observed, women had significantly lower estimates of the age at which female adolescents can make informed decisions about sexual activity than men, as did respondents who had children and were older. Working with children had little impact. The legal implications of these findings are discussed.