background: posterior urethral valve presenting in adulthood is uncommon. this can be an unusual cause of primary male infertility as a result of abnormalities in sexual function. case presentation: this report describes a 40 year old man who presented to us on account of inability to impregnate his wife after 2 years of marriage. history revealed poor stream of urine since childhood and passag...

Previous studies of the cricket Teleogryllus oceanicus have shown a paternity bias towards non-sibling males. Although non-kin-biased paternity could represent a mechanism of postcopulatory inbreeding avoidance by females, evolutionarily stable strategy (ESS) models of ejaculate evolution also predict that males should reduce their expenditure on the ejaculate when mating with their sisters. He...

Oogenesis in Drosophila requires a significant amount of phosphorus. Oocytes mature in follicles, each of which contains 15 highly polyploid, transcriptionally active chromosomes. We show that the demand for phosphorus is met in part from the male's ejaculate following mating. Females incorporate phosphorus-32 from radiolabelled males into their ovaries, specifically into their nucleic acids. M...

Although the primary function of mating is gamete transfer, male ejaculates contain numerous other substances that are produced by accessory glands and transferred to females during mating. Studies with several model organisms have shown that these substances can exert diverse behavioural and physiological effects on females, including altered longevity and reproductive output, yet a comprehens...

Sperm competition is widely recognized as a pervasive force of sexual selection. Theory predicts that across species increased risk of sperm competition should favor an increased expenditure on the ejaculate, a prediction for which there is much evidence. Sperm competition games have also been developed specifically for systems in which males adopt the alternative male mating tactics of sneakin...

Sexual selection, differences in reproductive success between individuals, continues beyond acquiring a mating partner and affects ejaculate size and composition (sperm competition). Sperm and seminal fluid have very different roles in sperm competition but both components encompass production costs for the male. Theoretical models predict that males should spend ejaculate components prudently ...

Despite the importance of quality semen used in artificial insemination to reproductive success dairy herds, few studies have estimated extent genetic variability traits. Even fewer quantified correlation between traits and male fertility. In this study, records 100,058 ejaculates collected from 2,885 Nordic Holstein bulls were estimate parameters for traits, including pre- postcryopreservation...

Reproductive efficiency represented by sexual desire, semen quality, testicular dimensions, and level of sex hormones are among the main components ram fertility, which affect fertility productivity herd. Since development testicles is related to reproductive activity ability fertilize, so measuring dimensions important in evaluating capacity rams. In addition, concentration testosterone reflec...