Search results for " Sexual"
showing 10 items of 475 documents
Sociodemographic and behavioural correlates of lifetime number of sexual partners: findings from the English Longitudinal Study of Ageing.
2018
BackgroundNo current data are available on correlates of lifetime sexual partners at older ages. This study aimed to explore correlates of the lifetime number of sexual partners in a sample of older adults.MethodData were from 3054 men and 3867 women aged ≥50 years participating in the English Longitudinal Study of Ageing. Participants reported their lifetime number of sexual partners and a range of sociodemographic characteristics and health behaviours. Multivariable multinomial logistic regression was used to examine correlates of lifetime number of sexual partners, with analyses performed separately for men and women and weighted for non-response.ResultsYounger age, being separated/divor…
Carry-over effects of conditions at the wintering grounds on breeding plumage signals in a migratory bird : roles of phenotypic plasticity and select…
2016
To understand the consequences of ever-changing environment on the dynamics of phenotypic traits, distinguishing between selection processes and individual plasticity is crucial. We examined individual consistency/plasticity in several male secondary sexual traits expressed during the breeding season (white wing and forehead patch size, UV reflectance of white wing patch and dorsal melanin coloration) in a migratory pied flycatcher (Ficedula hypoleuca) population over an 11-year period. Furthermore, we studied carry-over effects of three environmental variables (NAO, a climatic index; NDVI, a vegetation index; and rainfall) at the wintering grounds (during prebreeding moult) on the expressi…
Sexual and postmating reproductive isolation between allopatric Drosophila montana populations suggest speciation potential
2011
This work was funded by a European Commission Research Training Grant RTN2-2001-00049, the Centre of Excellence for Evolutionary Research at the University of Jyväskylä and a Marie Curie Initial Training Network, ‘Understanding the evolutionary origin of biological diversity’ (ITN-2008-213780 SPECIATION) Background: Widely distributed species with populations adapted to different environmental conditions can provide valuable opportunities for tracing the onset of reproductive incompatibilities and their role in the speciation process. Drosophila montana, a D. virilis group species found in high latitude boreal forests in Nearctic and Palearctic regions around the globe, could be an excellen…
Caution on the assessment of intestinal parasitic load in studying parasite-mediated sexual selection: the case of Blackbirds coccidiosis.
2009
6 pages; International audience; The parasite-mediated sexual selection (PMSS) theory has led to an increasing number of experimental studies essentially focussed on blood parasites. Currently, more research is being carried out on intestinal parasites in relationship to this theory. Before testing the theory with gastrointestinal parasites, it is important: (i) to determine an optimal research methodology to obtain an accurate assessment of parasite burden and (ii) to have information about life-history traits of the parasite to interpret data appropriately. In this study, we present data on oocyst output of Isosporaturdi in the faeces of blackbirds (Turdus merula) that illustrate the impo…
Intralocus sexual conflict for fitness: sexually antagonistic alleles for testosterone
2011
Intralocus sexual conflict occurs when a trait encoded by the same genetic locus in the two sexes has different optima in males and females. Such conflict is widespread across taxa, however, the shared phenotypic traits that mediate the conflict are largely unknown. We examined whether the sex hormone, testosterone (T), that controls sexual differentiation, contributes to sexually antagonistic fitness variation in the bank vole, Myodes glareolus . We compared (opposite-sex) sibling reproductive fitness in the bank vole after creating divergent selection lines for T. This study shows that selection for T was differentially associated with son versus daughter reproductive success, causing a …
Flexible parental care: Uniparental incubation in biparentally incubating shorebirds
2017
The relative investment of females and males into parental care might depend on the population’s adult sex-ratio. For example, all else being equal, males should be the more caring sex if the sex-ratio is male biased. Whether such outcomes are evolutionary fixed (i.e. related to the species’ typical sex-ratio) or whether they arise through flexible responses of individuals to the current population sex-ratio remains unclear. Nevertheless, a flexible response might be limited by the evolutionary history of the species, because one sex may have lost the ability to care or because a single parent cannot successfully raise the brood. Here, we demonstrate that after the disappearance of one pare…
Water temperature influences growth and gonad differentiation in European sea bass (Dicentrarchus labrax, L. 1758)
2016
The effect of rearing temperature on gonad differentiation and growth was evaluated in sea bass (Dicentrarchus labrax). One control group (CG, n = 60) and two experimental groups (EG1, n = 30; EG2, n = 30) were selected. CG was reared at 15.0 °C during 10 days post-hatch (dph) and at 19.0 °C throughout the remaining larval and post-larval development. EG1 was exposed to 14.5 °C from 1 to 50 dph, followed by an increase to 20 °C until sampling (176 dph). EG2 was exposed to 14.5 °C from 1 to 37 dph, followed by an increase to 20 °C until sampling (226 dph); 30 fish from CG were randomly sampled at 176 dph (CG1, control for EG1) and 30 fish were sampled at 226 dph (CG2, control for EG2). Weigh…
Masturbation to Orgasm Stimulates the Release of the Endocannabinoid 2-Arachidonoylglycerol in Humans
2017
Abstract Background Endocannabinoids are critical for rewarding behaviors such as eating, physical exercise, and social interaction. The role of endocannabinoids in mammalian sexual behavior has been suggested because of the influence of cannabinoid receptor agonists and antagonists on rodent sexual activity. However, the involvement of endocannabinoids in human sexual behavior has not been studied. Aim To investigate plasma endocannabinoid levels before and after masturbation in healthy male and female volunteers. Outcomes Plasma levels of the endocannabinoids 2-arachidonoylglycerol (2-AG), anandamide, the endocannabinoid-like lipids oleoyl ethanolamide and palmitoyl ethanolamide, arachido…
Development and psychometric properties of an instrument for the Assessment of Sexual Behaviour and Knowledge of people with Intellectual Disability
2020
Background This paper presents psychometric properties of an instrument for the Assessment of Sexual Behaviour and Knowledge of people with Intellectual Disability (ASBKID), other‐reported by professionals who are in daily contact with them. Methods and procedures Assessments of 236 individuals with intellectual disability were obtained from 100 professionals. Results Confirmatory factor analysis revealed a four‐factor structure: concern about the user's inappropriate or uninhibited sexual behaviour; perception of the user's knowledge about privacy and social norms; perception of the user's knowledge about sexuality; and concerns about the user's sexuality. A multi‐group CFA was also conduc…
Gut microbiota steroid sexual dimorphism and its impact on gonadal steroids: influences of obesity and menopausal status
2020
[Background]: Gonadal steroid hormones have been suggested as the underlying mechanism responsible for the sexual dimorphism observed in metabolic diseases. Animal studies have also evidenced a causal role of the gut microbiome and metabolic health. However, the role of sexual dimorphism in the gut microbiota and the potential role of the microbiome in influencing sex steroid hormones and shaping sexually dimorphic susceptibility to disease have been largely overlooked. Although there is some evidence of sex-specific differences in the gut microbiota diversity, composition, and functionality, the results are inconsistent. Importantly, most of these studies have not taken into account the go…