Determining the sex of Little Penguins (Eudyptula minor) in northern Bass Strait using morphometric measurements

In avian species with no obvious differences in plumage or body size between the sexes, such as penguins, discriminant function analysis (DFA) of morphometric measurements that display sexual dimorphism can provide a simple and rapid means of determining sex in the field. Like most other penguin species, the Little Penguin (Eudyptula minor) displays sexual dimorphism in bill shape and size. In the present study, discriminant functions (DFs) were developed for sexing adult Little Penguins at two colonies in northern Bass Strait, Victoria, Australia, and their accuracies were compared with those obtained previously in other parts of the species' range. Backwards stepwise DFA indicated that birds at Phillip Island can be sexed with an accuracy of 91% using a single measurement of bill depth (>13.33 mm classed as males). Similar analyses at Gibson Steps produced a DF incorporating bill length, bill depth and head length [although the model with the greatest accuracy when applied to birds from Phillip Island (91%) also contained only bill depth]. Published DFs derived in New Zealand had accuracies of 50–85% when applied to birds from Phillip Island and Gibson Steps, supporting earlier suggestions that DFs are not applicable across subspecies of the Little Penguin. In contrast, there was little difference between the accuracy of the DFs in the present study and that previously derived for the same subspecies in Tasmania when applied to birds from Phillip Island (89%) and Gibson Steps (92%). However, as the degree of variation in bill size within a subspecies is unknown it may still be prudent to derive colony-specific DFs.

Not the same : a comparison of female and male clients seeking treatment from problem gambling counselling services

Previous studies of problem gamblers portray this group as being almost exclusively male. However, this study demonstrates that females comprised 46% of the population (n = 1,520) of persons who sought assistance due to concerns about their gambling from the publicly-funded BreakEven counselling services in the state of Victoria, Australia, in one 12-month period. This suggests that the model of service delivery which is community based counselling on a non-residential basis may be better able to attract female clients than treatment centres where males predominate such as veterans centres. A comparative analysis of the social and demographic characteristics of female and male gamblers within the study population was undertaken. As with previous studies, we have found significant differences between males and females who have sought help for problems associated with their gambling. Gender differences revealed in this study include females being far more likely to use electronic gaming machines (91.1% vs. 61.4%), older (39.6 years vs. 36.1 years), more likely to be born in Australia (79.4% vs. 74.7%), to be married (42.8% vs. 30.2%), living with family (78.9% vs. 61.5%) and to have dependent children (48.4% vs. 35.7%), than males who present at these services. Female gamblers (A$7,342) reported average gambling debts of less than half of that owed by males (A$19,091). These gender differences have implications for the development and conduct of problem gambling counselling services as it cannot be assumed that models of service which have demonstrated effectiveness with males will be similarly effective with females.

Boys want sex, girls want commitment: does this trade-off still exist?

Editorial. Examines the existence of the trade-off between a men's sexual cravings and women's yearning for a relationship commitment Recognition of the increasing frequency of sexual experience among adolescent boys and girls; Observation of the liberalization of attitudes regarding pre-marital sexual experience; Interpretation of the dating code adopted by both sexes; Role of sex in a male-female relationship; Consideration that adolescent boys and girls want and experience the same types of sexual and affectional dimensions.

Marriage: every bride`s ambition satisfied?

It has been acknowledged through sociobiological research that women seek men who will provide good genes to produce strong healthy offspring, and men seek women who are attractive, because these women are seen to be most suitable for producing fit children. According to the author in last two centuries, in western societies, mate selection has also frequently led to marriage. If the man fails to meet these genetic standards, women may be driven to have extramarital affairs so that they can obtain good genetic stock, but will still keep their husband if he provides good support resources for her and her children.

Is sex-specific mass gain in Cory's shearwaters Calonectris diomedea related to begging and steroid hormone expression?

Mass differences between the sexes of dimorphic bird species often appear early in the nestling development. But how do adults know how much to feed a chick in a sexually dimorphic species? Do chicks of the heavier sex beg more? We studied begging in Cory’s shearwaters Calonectris diomedea, a species with heavier adult and juvenile males than females. We found that begging rates and call numbers were not different between male and female chicks, but parameters of begging intensity differed between the sexes in their relationship to chick body condition. For the same body condition, males had significantly higher begging call numbers and rates. Acoustical parameters, which were analysed semi-automatically, included the lengths of call and silence intervals, the minimum, mean and maximum frequency in a call and the number of frequency peaks within a call. We found no consistent differences of acoustic begging call elements between the sexes. Male and female chicks did not differ in the levels of the steroid hormones testosterone or corticosterone in the second quarter of the nestling period, and the mechanism leading to sex-related differences in begging rates for a given body condition remains unknown.

Sex reversal in Nile tilapia (Oreochromis niloticus Linnaeus) by androgen immersion

Two experiments were conducted to investigate the efficacy of three androgens applied through immersion treatments on the sex ratio of Nile tilapia (Oreochromis niloticus L.) fry. In experiment 1, 14 days post-hatching (DPH) larvae were exposed to a single immersion treatment in 17α-methyltestosterone (MT), 17α-methyldihydrotestosterone (MDHT) or 17α-ethynyltestosterone (ET) at 200, 600 and 1800 μg L⁻¹ over 4 h (130 larvae per treatment). In experiment 2, Nile tilapia larvae were exposed to the higher androgen concentration (1800 μg L⁻¹) applied as either a single immersion (14 DPH) or double immersion (10 and 14 DPH) over 4 h (125 larvae per treatment). Change in sex proportion within each experiment as well as between experiments was analysed by the chi-square test. In experiment 1, MT, MDHT and ET were equally effective in significantly increasing the proportion of males when applied at 1800 μg L⁻¹ (86.0%, 90.0% and 86.7% respectively). At 200 μg L⁻¹ none of the androgens altered sex ratio. At 600 μg L⁻¹, only MDHT slightly, but significantly skewed the sex ratio towards males (73.0%). In experiment 2, a single immersion treatment at 14 DPH (1800 μg L⁻¹) significantly increased the proportion of males, but at this time the response was significantly hormone dependent (MDHT, 100.0%; MT, 91.6%; ET, 76.9%). When compared with a single immersion, two-immersion treatments significantly increased the proportion of males in the MT-treated group (from 91.6% to 98.3%), decreased the proportion of males in the MDHT group (from 100.0% to 93.4%) and had no significant effect the ET-treated group (change from 76.9% to 82.5%). The overall comparison of the sex ratio among same treatments from different experiments (a single immersion in 1800 μg L⁻¹) was not significantly different.

Effects of the aromatase inhibitor Fadrozole on plasma sex steroid secretion and oocyte maturation in female coho salmon (Oncorhynchus kisutch) during vitellogenesis

17β-estradiol, 17α-20β-dihydroxy-4-pregnen-3-one (17α-20β-P), and testosterone levels were measured in plasma samples obtained from vitellogenic coho salmon (Oncorhynchus kisutch) before and 32 days after injection of the aromatase inhibitor Fadrozole (AI). Plasma 17β-estradiol levels decreased significantly 6 h after injection in all AI treated fish. The higher the dose the longer the maintenance of low plasma 17β-estradiol levels. Inversely, plasma 17α-20β-P increased significantly 6 h after injection in all AI treated fish, and the higher the dose the longer the maintenance of high plasma 17α-20β-P levels. At 48 h after injection plasma testosterone levels were significantly higher in the AI treated groups. The oocyte maturation index showed that multiple injections with AI retarded oocyte development. Besides, oocyte diameter and GSI were lower in the same group, which presented high incidence of atresia of vitellogenic oocytes. The ovarian follicles and brain of the fish which received multiple injections secreted less 17β-estradiol, in vitro. These findings suggest that aromatase inhibitors such as Fadrozole may have a potential as a tool to regulate sexual development in salmon.

Retracted: Experimental evidence that maternal corticosterone controls adaptive offspring sex ratios

1. Sex allocation theory has received considerable attention, yet the mechanism(s) by which mothers skew offspring sex ratios remain unknown. In birds, females are the heterogametic sex, which potentially gives them control of whether gametes will be male or female. How females might control the sex of the gamete is unclear, but one possibility is that variation in steroid hormones may mediate this process. 2. We experimentally altered circulating levels of corticosterone in female Gouldian finches (Erythrura gouldiae), a species that demonstrates both extreme stress responses and extreme offspring sex ratio biases when breeding with a low-quality (genetically incompatible) partner. 3. During egg production, individual females received both corticosterone and metyrapone (a corticosterone-synthesis inhibitor) implants, in random order, to induce both high and low levels of circulating stress hormones (within physiological limits). 4. We found that females with elevated corticosterone levels produced male-biased sex ratios, but when the same females were treated with metyrapone they produced female-biased offspring sex ratios. 5. These stress responses are adaptive because females constrained to breeding with low-quality males can substantially increase their fitness by overproducing sons. Changes in maternal corticosterone levels during stressful situations, such as the quality of a breeding partner, may provide an endocrine mechanism that can be exploited for strategic sex allocation.

Sex differences in the Toll-like receptor-mediated response of plasmacytoid dendritic cells to HIV-1

Manifestations of viral infections can differ between women and men, and marked sex differences have been described in the course of HIV-1 disease. HIV-1-infected women tend to have lower viral loads early in HIV-1 infection but progress faster to AIDS for a given viral load than men. Here we show substantial sex differences in the response of plasmacytoid dendritic cells (pDCs) to HIV-1. pDCs derived from women produce markedly more interferon-alpha (IFN-alpha) in response to HIV-1-encoded Toll-like receptor 7 (TLR7) ligands than pDCs derived from men, resulting in stronger secondary activation of CD8(+) T cells. In line with these in vitro studies, treatment-naive women chronically infected with HIV-1 had considerably higher levels of CD8(+) T cell activation than men after adjusting for viral load. These data show that sex differences in TLR-mediated activation of pDCs may account for higher immune activation in women compared to men at a given HIV-1 viral load and provide a mechanism by which the same level of viral replication might result in faster HIV-1 disease progression in women compared to men. Modulation of the TLR7 pathway in pDCs may therefore represent a new approach to reduce HIV-1-associated pathology.

Glomerular hypertrophy in subjects with low nephron number: contributions of sex, body size and race

Background. We have shown that low nephron number (Nglom) is a strong determinant of individual glomerular volume (IGV) in male Americans. However, whether the same pattern is present in female Americans remains unclear. The contributions of body surface area (BSA) and race to IGV in the context of Nglom also require further evaluation. Methods. Kidneys without overt renal disease were collected at autopsy in Mississippi, USA. The extremes of female Nglom were used to define high and low N glom for both sexes. Nglom and IGV were estimated by design-based stereology. A total of 24 African and Caucasian American females (n = 12 per race; 6 per Nglom extreme) were included. These subjects were subsequently matched to 24 comparable males by age and Nglom and to 18 additional males by age, Nglom and BSA. Results. IGV average and variance were very similar in female African and Caucasian Americans with high and low Nglom. Males with low Nglom from both races showed greater IGV average and variance than comparable females matched by age and Nglom. These differences in IGV between sexes were not observed in Caucasian Americans with low Nglom that were matched by age, Nglom and BSA. In contrast, glomeruli from African Americans were larger than those from Caucasian Americans, especially in subjects with high Nglom. Conclusions. While female Americans with low Nglom did not show glomerular hypertrophy, comparable males with low Nglom showed marked glomerular hypertrophy that was closely associated with high BSA. Glomerular size in African Americans may be confounded by multiple additional factors. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

All signals are not equal: acoustic signalling of individuality, sex and breeding status in a cooperative breeder

Repeated interactions between individuals in socially living animals select for the evolution of signals that convey information identifying individuals or categories of individuals, which may enable the discrimination of familiar versus unfamiliar individuals. Such information may help animals maximize their inclusive fitness by adjusting their own behaviour, allowing them to avoid conflict, preferentially direct help and/or ignore unreliable individuals. Acoustic signals in birds provide the potential to encode individual-specific information. We examined the degree to which individual identity, sex, breeding status, group membership and genetic relatedness were related to variability in six different call types, which occurred across a variety of different behavioural contexts in the apostlebird, Struthidea cinerea, a socially living and cooperatively breeding Australian passerine. We demonstrated that not all calls reflected the same extent of information. Of the six call types, call variation was related to individual identity in three call types, breeding status in two call types and sex and group relatedness in one call type. Finally, variation in two call types was not related to any of the measured variables. Our results suggest that some, but not all, acoustic signals in apostlebirds may be selected for individual distinctiveness between individuals and categories of individuals (male versus female, breeder versus nonbreeder), and these signals may be important in determining levels of cooperation and interaction between individuals in this cooperatively breeding society. © 2014 The Association for the Study of Animal Behaviour.

Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013

Background: Up-to-date evidence on levels and trends for age-sex-specific all-cause and cause-specific mortality is essential for the formation of global, regional, and national health policies. In the Global Burden of Disease Study 2013 (GBD 2013) we estimated yearly deaths for 188 countries between 1990, and 2013. We used the results to assess whether there is epidemiological convergence across countries. Methods We estimated age-sex-specific all-cause mortality using the GBD 2010 methods with some refinements to improve accuracy applied to an updated database of vital registration, survey, and census data. We generally estimated cause of death as in the GBD 2010. Key improvements included the addition of more recent vital registration data for 72 countries, an updated verbal autopsy literature review, two new and detailed data systems for China, and more detail for Mexico, UK, Turkey, and Russia. We improved statistical models for garbage code redistribution. We used six different modelling strategies across the 240 causes; cause of death ensemble modelling (CODEm) was the dominant strategy for causes with sufficient information. Trends for Alzheimer's disease and other dementias were informed by meta-regression of prevalence studies. For pathogen-specific causes of diarrhoea and lower respiratory infections we used a counterfactual approach. We computed two measures of convergence (inequality) across countries: the average relative difference across all pairs of countries (Gini coefficient) and the average absolute difference across countries. To summarise broad findings, we used multiple decrement life-tables to decompose probabilities of death from birth to exact age 15 years, from exact age 15 years to exact age 50 years, and from exact age 50 years to exact age 75 years, and life expectancy at birth into major causes. For all quantities reported, we computed 95% uncertainty intervals (UIs). We constrained cause-specific fractions within each age-sex-country-year group to sum to all-cause mortality based on draws from the uncertainty distributions. Findings Global life expectancy for both sexes increased from 65·3 years (UI 65·0-65·6) in 1990, to 71·5 years (UI 71·0-71·9) in 2013, while the number of deaths increased from 47·5 million (UI 46·8-48·2) to 54·9 million (UI 53·6-56·3) over the same interval. Global progress masked variation by age and sex: for children, average absolute differences between countries decreased but relative differences increased.For women aged 25-39 years and older than 75 years and for men aged 20-49 years and 65 years and older, both absolute and relative differences increased. Decomposition of global and regional life expectancy showed the prominent role of reductions in age-standardised death rates for cardiovascular diseases and cancers in high-income regions, and reductions in child deaths from diarrhoea, lower respiratory infections, and neonatal causes in low-income regions. HIV/AIDS reduced life expectancy in southern sub-Saharan Africa. For most communicable causes of death both numbers of deaths and age-standardised death rates fell whereas for most non-communicable causes, demographic shifts have increased numbers of deaths but decreased age-standardised death rates. Global deaths from injury increased by 10·7%, from 4·3 million deaths in 1990 to 4·8 million in 2013; but age-standardised rates declined over the same period by 21%. For some causes of more than 100 000 deaths per year in 2013, age-standardised death rates increased between 1990 and 2013, including HIV/AIDS, pancreatic cancer, atrial fibrillation and flutter, drug use disorders, diabetes, chronic kidney disease, and sickle-cell anaemias. Diarrhoeal diseases, lower respiratory infections, neonatal causes, and malaria are still in the top five causes of death in children younger than 5 years. The most important pathogens are rotavirus for diarrhoea and pneumococcus for lower respiratory infections. Country-specific probabilities of death over three phases of life were substantially varied between and within regions. Interpretation For most countries, the general pattern of reductions in age-sex specific mortality has been associated with a progressive shift towards a larger share of the remaining deaths caused by non-communicable disease and injuries. Assessing epidemiological convergence across countries depends on whether an absolute or relative measure of inequality is used. Nevertheless, age-standardised death rates for seven substantial causes are increasing, suggesting the potential for reversals in some countries. Important gaps exist in the empirical data for cause of death estimates for some countries; for example, no national data for India are available for the past decade.

The influence of sex, temperament, risk-taking and mental health on the emergence of gambling: a longitudinal study of young people

There are a host of complex and interlinked psychological, social and biological factors involved in the development of problem gambling (PG). While existing research, which is predominantly cross-sectional, shows that emerging adulthood is a critical period for PG, the early risk factors for PG are currently unknown. Here, we recruited a sample of 156 early adolescents with no history of PG (mean age 12.6 years) and longitudinally followed them up into late adolescence (mean age 18.9 years) to investigate the role of sex, risk-taking behaviour and changes in temperament and psychiatric symptoms in the evolution of risky gambling behaviour. There were sex-independent effects of temperament and risk-taking behaviour, with greater developmental increases in temperamental frustration (i.e. negative affectivity), greater developmental decreases in temperamental attention (i.e. effortful control) and greater involvement in risky behaviours, such as alcohol use, predicting greater likelihood of being in the risky gambling group. In addition, there were sex-dependent effects whereby higher levels of baseline aggression in females and lower levels of the same in males were more predictive of risky gambling. These findings highlight how sex-dependent and independent factors across the early- to mid-adolescent period influence the occurrence of gambling later in life.

Discordant age and sex-specific trends in the incidence of a first coronary heart disease event in Western Australia from 1996 to 2007

OBJECTIVE: To determine age- and sex-specific population trends in fatal and non-fatal first coronary heart disease (CHD) events in Western Australia from 1996 to 2007. DESIGN: Longitudinal retrospective population study. SETTING: State-wide population. PATIENTS: All residents aged 35-84 years during 1996-2007 who died or were hospitalised with a principal diagnosis of acute CHD. DATA SOURCES: Person-linked file of mortality and morbidity records. MAIN OUTCOME MEASURES: Age-standardised (35-84 years) and age-specific (35-54, 55-69, 70-84 years) rates by gender for a first CHD event were calculated with a 10-year lead-in period to define first events. RESULTS: From 1996 to 2007 there were 36 631 first CHD events, including 8518 (23%) fatal cases in those aged 35-84 years. Overall, age-adjusted rates for fatal first CHD declined 5.3%/year in men (95% CI -6.1% to -4.6%) and 6.5%/year in women (95% CI -7.5% to -5.5%). However, age-specific fatal first CHD rates were neutral in both men aged 35-54 years (0.1%/year; 95% CI -1.8% to 2.1%) and women of the same age, (-1.6%/year; 95% CI -5.6% to 2.5%). Age-specific trends in non-fatal CHD rates reflected the same trends in fatal CHD events in men and women, with rates reportedly increasing in women aged 35-54 years (2.5%/year (95% CI 1.1% to 3.9%). CONCLUSION: The age-specific decline in fatal and non-fatal first CHD rates in older men and women was not observed in those aged 35-54 years. These novel findings provide evidence for a levelling in the CHD incidence rates in younger adults and puts renewed importance on primary prevention in this group.