Search results for "Sexual behavior"
showing 10 items of 304 documents
Effect of genes, social experience, and their interaction on the courtship behaviour of transgenic Drosophila males
2005
Behaviour depends (a) on genes that specify the neural and non-neural elements involved in the perception of and responses to sensory stimuli and (b) on experience that can modulate the fine development of these elements. We exposed transgenic and control Drosophila melanogaster males, and their hybrids, to male siblings during adult development and measured the contribution of genes and of experience to their courtship behaviour. The transgene CheB42a specifically targets male gustatory sensillae and alters the perception of male inhibitory pheromones which leads to frequent male–male interactions. The age at which social experience occurred and the genotype of tester males induced a varia…
Chemosensory assessment of sperm competition levels and the evolution of internal spermatophore guarding
2006
Males of many species adjust their reproductive behaviour according to the perceived risk of sperm competition. Although this phenomenon is widespread in insects and other animals, the mechanisms that allow mates to assess sperm competition levels remain largely unexplored. In this study, we analysed the mating behaviour of pairs ofTenebrio molitorbeetles under three odour treatments representing increasing levels of sperm competition risk (SCR) and sperm competition intensity (SCI). Copula duration and male and female post-copulatory behaviour varied significantly with odour treatment. Both copula duration and post-copulatory associations (PCAs) increased significantly in odour treatments …
Pairing success and sperm reserve of male Gammarus pulex infected by Cyathocephalus truncatus (Cestoda: Spathebothriidea).
2011
SUMMARYManipulative parasites with complex life cycles are known to induce behavioural and physiological changes in their intermediate hosts. Cyathocephalus truncatus is a manipulative parasite which infects Gammarus pulex as intermediate host. G. pulex males display pre-copulatory mate guarding as a response to male-male competition for access to receptive females. In this paper, we tested the influence that C. truncatus-infection might have on male G. pulex sperm number and pairing success. We considered 3 classes of G. pulex males in our experiments: (i) uninfected males found paired in the field, (ii) uninfected males found unpaired in the field, or (iii) infected males found unpaired i…
An inhibitory sex pheromone tastes bitter for Drosophila males
2007
1932-6203 (Electronic) Journal Article; Sexual behavior requires animals to distinguish between the sexes and to respond appropriately to each of them. In Drosophila melanogaster, as in many insects, cuticular hydrocarbons are thought to be involved in sex recognition and in mating behavior, but there is no direct neuronal evidence of their pheromonal effect. Using behavioral and electrophysiological measures of responses to natural and synthetic compounds, we show that Z-7-tricosene, a Drosophila male cuticular hydrocarbon, acts as a sex pheromone and inhibits male-male courtship. These data provide the first direct demonstration that an insect cuticular hydrocarbon is detected as a sex ph…
A trade-off between sexual signalling and immune function in a natural population of the drumming wolf spider Hygrolycosa rubrofasciata.
2005
The field of ecological immunology is ultimately seeking to address the question ‘Why is there variation in immune function?’ Here, we provide experimental evidence that costs of ubiquitous sexual signals are a significant source of variation in immune function. In the mating season, males of the wolf spider Hygrolycosa rubrofasciata drum against dry leaves while wandering around the habitat searching for receptive females. According to a previous study, the male metabolic rate during the drumming increases 22-fold compared to the resting metabolic rate. In the present study, we examined whether investment in costly courtship drumming decreases male immune function in a wild population of H…
Female-released sex pheromones mediating courtship behavior in Lysiphlebus testaceipes males.
2013
Ethological aspects and chemical communication at close-range between the sexes of Lysiphlebus testaceipes Cresson (Hymenoptera: Braconidae) have been investigated through behavioral bioassays and chemical analysis. The attractiveness toward males of whole-body extracts of females and males in hexane and acetone was evaluated, adopting male fanning behavior as a key behavioral component. Also, the activity of polar and nonpolar fraction of female-body extract in hexane obtained using solid-phase extraction technique was investigated. In order to identify cuticular compounds, male and female whole-body extracts with hexane and acetone were analyzed by gas chromatography-mass spectrometry. Th…
Sexual behavior and suicide attempts among adolescents aged 12–15 years from 38 countries: A global perspective
2020
BACKGROUND: The aim was to investigate the relationship between sexual behaviors and suicide attempts by using data from 38 countries from four World Health Organization regions. METHODS: Cross-sectional data from 116,820 adolescents aged 12-15 years participating in the Global School-based Student Health Survey 2009-2016 were analyzed. Data on sexual behaviors were collected: (i) ever having had intercourse; among those who reported having had intercourse, (ii) multiple (≥2) lifetime sexual partners and (iii) condom use in last sexual intercourse and past 12-month suicide attempts were self-reported. Associations were analyzed using multivariable logistic regression. RESULTS: The prevalenc…
Association between cannabis use and sexual behavior among adolescents aged 12-15 years in 21 low- and middle-income countries.
2019
Abstract Aims To investigate the relationship between cannabis use and two sexual behaviors (ever had sex, multiple partners) in a large representative sample of adolescents aged 12–15 years from 21 low- and-middle income countries. Methods Data from 84,867 adolescents aged 12–15 years participating in the Global School-based Student Health Survey were analyzed. Participants reported lifetime frequency of cannabis use (analyzed as 0, 1–2, 3–19 or ≥ 20 times), whether they had ever had sexual intercourse (yes/no) and, if yes, their lifetime number of sexual partners. We used multivariable logistic regression to analyze associations, adjusting for a range of relevant covariates. Results 12.7%…
Adolescent sexual behavior during periods of increase and decrease in the abortion rate.
2009
OBJECTIVE: To study changes in adolescent sexual behavior in periods of increase (1994-2000) and decrease (2001-2007) in the abortion rate. METHODS: School surveys with self-administered questionnaires were carried out annually among eighth graders (mean age 14.8 years) and ninth graders (mean age 15.8 years) (N=286665) in 1996/1997 and 2006/2007. Schools participated biennially. The proportions of respondents reporting noncoital (kissing light petting heavy petting) and coital (ever had sexual intercourse intercourse at least 10 times at least three partners) sexual experience and nonuse of contraception were studied. RESULTS: Among adolescents both coital and noncoital sexual experiences …
Attraction to male pheromones and sexual behaviour show different regulatory mechanisms in female mice.
2004
In rodents, female sexual behaviour is under hormonal control. The attraction females show for male-derived nonvolatile chemicals (pheromones) can be regarded as the first step of this behaviour, but it is unknown whether this attraction is also modulated by sexual steroids. To test this possibility, ovariectomized adult female mice with no experience of chemical signals from adult males were randomly assigned to four groups that received oil (control), progesterone, estradiol (E) or estradiol+progesterone (E+P) injections, respectively. Females were then tested for their attraction to male-soiled bedding and, subsequently, for their proceptive behaviour when confronted to adult males. Fema…