In this article, we provide a concise review of the past and current literature on the neglected influence of progesterone on male sexual behavior. Although there has been increased interest in all aspects of male sexual function, and the importance of androgens in the regulation of male copulatory behavior has long been well documented, knowledge of the role of progesterone on male sexual behavior is still patchy. Very little human data exist on this theme, and most of the literature concerns animal research, in particular reptiles and rodents. This review attempts to outline specific progesterone mechanisms involved in male sexual behavior, showing that this hormone plays a more relevant role in the control of male sexual behavior than commonly assumed. Exploring the neuroendocrine mechanisms of progesterone in the sexual behavior of males may provide insights into the regulation of sexuality in this gender. (c) 2005 Elsevier B.V. All rights reserved ...
There are two reasons why researchers are interested in the phenotypic relationship between the expression of male secondary sexual characters (SSCs) and ejaculate quality (defined as sperm/ejaculate traits that are widely assumed to increase female fertility and/or sperm competitiveness). First, if the relationship is positive then females could gain a direct benefit by choosing more attractive males for fertility assurance reasons (the phenotype-linked fertility hypothesis). Second, there is much interest in the direction of the correlation between traits favoured by pre-copulatory sexual selection (i.e. affecting mating success) and those favoured by post-copulatory sexual selection (i.e. increasing sperm competitiveness). If the relationship is negative this could lead to the two forms of selection counteracting each other. Theory predicts that the direction of the relationship could be either positive or negative depending on the underlying genetic variance and covariance in each trait, ...
A large body of literature has centred on whether female resistance evolves as a result of sexual conflict or as a form of female choice for superior mates (also known as resistance as a screen, or resistance as choice) [50,101-103]. According to this hypothesis, open-ended female resistance will ensure that a female copulates only with dominant males that are best able to overcome female resistance; male offspring will be superior competitors/coercers, and female resistance will evolve through the indirect benefits of their superior coercive male offspring [50,101-103]. This type of screening has been hypothesized to occur during pre-copulatory struggles, and during and/or after copulation via cryptic female choice mechanisms [50]. The main argument against the resistance as a screen hypothesis is that the magnitude of the direct costs imposed by coercive males may be much greater than the magnitude of any potential indirect benefit that females may gain [56], but this issue is far from ...
TY - JOUR. T1 - Mounting and lordosis behavior in androgen primed ovariectomized rats. T2 - Effect of dorsal deafferentation of the preoptic area and hypothalamus. AU - Yamanouchi, K.. PY - 1980. Y1 - 1980. N2 - Daily injections of 500 μg testosterone propionate (TP) for 21 days induced mounting behavior in all of 10 castrated male rats and the mean mount frequency (MF) for 30 min was 32.4±6.6 (mean±S.E.). The same treatment with TP induced mounting behavior in 6 out of 8 ovariectomized rats (female control), but the mean MF was 2.8±0.7. Eight out of 12 ovariectomized rats who received a horizontal half-circle cut anterior to the anterior commissure (anterior roof deafferentation, ARD) with an L-shaped Halasz knife displayed mounting behavior more frequently and their MF was 14.5±5.1. The latent period between the introduction of a receptive female and the occurrence of the first mounting (mount latency, ML) in ARD rats was significantly shorter than that of the female controls. A half ...
Male contests for access to receptive females are thought to have selected for the larger male body size and conspicuous weaponry frequently observed in mammalian species. However, when females copulate with multiple males within an oestrus, male reproductive success is a function of both pre- and post-copulatory strategies. The relative importance of these overt and covert forms of sexual competition has rarely been assessed in wild populations. The Soay sheep mating system is characterized by male contests for mating opportunities and high female promiscuity. We find that greater horn length, body size and good condition each independently influence a males ability to monopolize receptive females. For males with large horns at least, this behavioural success translates into greater siring success. Consistent with sperm-competition theory, we also find that larger testes are independently associated with both higher copulation rates and increased siring success. This advantage of larger testes ...
Fingerprint Dive into the research topics of Testosterone, endurance, and Darwinian fitness: Natural and sexual selection on the physiological bases of alternative male behaviors in side-blotched lizards. Together they form a unique fingerprint. ...
In this study, we show for both sexes of the dark-eyed junco that EPO have higher lifetime reproductive success than WPO. To our knowledge, this is the first case in which EPP has been shown to increase lifetime reproductive success of adult offspring in a free-living songbird. In the only similar previous study, the reproductive success of adult female F1 EPO coal tits (Parus ater) did not differ from that of female F1 WPO, and adult male F1 EPO had lower apparent (social) reproductive success than did male F1 WPO. However, extra-pair siring success of F1 males was not measured, and therefore adult genetic reproductive success could not be calculated [16-18].. In many species, there is no obvious benefit to female fitness from mating with an extra-pair male, and some have even hypothesized that extra-pair mating should carry a cost to offspring production or survival [34,35] (although not in juncos [21]; see also [36]). This lack of a cost to females, combined with the observed twofold benefit ...
The realization of polyandry is also contributing to a much more dynamic view of social conflicts. The most obvious forms of conflict relevant to polyandry are conflicts arising among members of the same sex and between males and females over reproductive decisions.. On the one hand, polyandry creates potential for conflict over some reproductive decisions such as cryptic female choice and parental care. On the other hand, it may reduce potential for sexual conflict over other reproductive decisions such as mating rates by weakening the male and increasing the female Bateman gradient. Although the notion that polyandry creates potential for intra- and inter-sexual conflict is not new, studies of sexual conflict have up until recently ignored the diversity of proximate mechanisms through which mating and sperm competition can impact female fitness. These mechanisms can have fundamental repercussions for the fitness pay-offs of sexual rivals and sexual partners. For example, the gonadotropic ...
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The genome of an infant who lived in Alaska thousands of years ago represents a previously unknown group of humans called Ancient Beringians, who share a common lineage with other Native Americans. 0 Comments. ...
Sperm competition is the competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and variety of mates increases a females chance to produce more viable offspring. However, multiple mates for a female means an individual male has decreased chances of producing offspring. Sperm competition is an evolutionary pressure on males, and has led to the development of adaptations to increase males chance of reproductive success. Sperm competition results in a sexual conflict of interest between males and females. Males have evolved several defensive tactics including: mate-guarding, mating plugs, and releasing toxic seminal substances to reduce female re-mating tendencies to cope with sperm competition. Offensive tactics of sperm competition involve direct interference by one male on the reproductive success of another male, for instance by ...
The seminal fluid of male Drosophila contains a cocktail of proteins that have striking effects on male and female fitness. In D. melanogaster, seminal fluid proteins affect female receptivity, ovulation, oogenesis, sperm storage, sperm competition and mating plug formation. In addition, the seminal fluid contains antibacterial peptides and protease inhibitors. Some seminal fluid-encoding genes also show high rates of evolutionary change, exhibiting both significant between-species divergence and within-species polymorphism. Seminal fluid protein genes are expressed only in males, begging the question of how and why the reproductive processes of females are influenced by males. In this review I address these issues by bringing together evidence for the function, evolution, diversification, and maintenance of variation in, seminal fluid-mediated traits.
TY - JOUR. T1 - Sexual behavior of male pigs. AU - Hemsworth, Paul Hamilton. AU - Tilbrook, Alan John. PY - 2007. Y1 - 2007. N2 - Two major characteristics of males that affect the likelihood of achieving copulation are the sexual motivation and mating competency of the male. The behavior of domestic animals, including their sexual behavior, is dependent upon a complex interaction between the organism s internal and external environment. In male pigs, as in other mammalian species, it is clear that testicular steroids are required to maintain sexual behavior and testosterone plays a critical role. Consistent with studies in other species, it is apparent in male pigs that there is a threshold circulating concentration of androgens and/or estrogens required to maintain sexual behavior and that the level of sexual motivation is unrelated to levels of sex steroids providing these are adequate for normal sexual behavior. Key aspects of the external environment that affect the sexual behavior of the ...
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This study showed that two reproductive hormones from different chemical classes, PGF2α and E2, stimulate sexual displays in females of a single fish species. PGF2α, in particular, was very effective in recovering sexual behaviours after ovariectomy. The injection of this hormone 45 min before testing into females ovariectomized 7 days before, recovered the frequency of both female approaches to the males nest and courtship displays towards the nesting male to levels similar to those of intact sham females. The positive effect of this hormone on nuptial coloration was, however, less pronounced. The role of prostaglandins in the induction of sexual behaviour in females has been demonstrated in several fishes with external fertilization: paradise fish, Macropodus opercularis [32], black acara Cichlasoma bimaculatum [33] and barb Puntius gonionotus [34]. Interestingly, administration of PGF2α to non-receptive females of the anuran Bufo americanus induced female phonotaxis behaviour towards male ...
Whether females can obtain genetic benefits from mate choice is contentious, and the main problem faced by previous studies of natural populations is that many factors other than paternal genes contribute to offspring fitness. Here, we use comparisons bet. ...
DA stresses that colour vision is very important in primates, not only because colour is used in sexual displays such as advertising a females receptiveness to mating [p. 275], but also to identify ripe fruit [p.247] and to select nutritious leaves [p. 255]. This section discusses these points in more detail and explains how the visual system in primates is able to detect colour.. White light is composed of light of different wavelengths, from 300-800 nanometres (nm); 1 nm is on ...
Although I enjoyed this paper quite a bit, and it seemed perfect fodder for some clever fun in photoshop (actually by E. Lu, see above), I also felt that that the study had some methodologically weak areas. For instance, the authors failed to take advantage of a new phylogenetic logistic regression procedure by Ives & Garland [2010], which seems ideally suited to their data. (In their defense, the method is brand new.) Consequently, however, the authors found themselves of the unfortunate position of using an arbitrary scoring system to estimate size-related reproductive skew: adding 1 point for the presence of pronounced sexual dichromatism, for example, and subtracting 1 point for alternative reproductive tactics (which might decrease the advantage of large male size) . With a phylogenetic multivariable logistic regression, the authors could have tested for an association between the log-odds of protogyny and each of their proxies for size-based reproductive skew (which also included ...
In the bird world, male and female blue tits are hard to distinguish for the human observer. However, in the UV-range, visible to birds, the male is much more colourful. A closer look at the monogamous mating system of these birds again reveals that all is not what it seems: in every second nest there are chicks that are not related to the care-giving father. An already mated male can increase the number of his offspring by siring extra-pair offspring in other nests than the one he cares for with his mate. Emmi Schlicht and Bart Kempenaers of the Max Planck Institute for Ornithology in Seewiesen investigated whether this could be the driving force behind the evolution of sexual dimorphism. However, their findings suggest that effects of extra-pair paternity are limited, and cuckoldry can even reduce the intensity of sexual selection.
Hear girl complaining about how men are pigs Explain that its partly her fault, since female mate selection determines course of evolution Science Major Mouse
Sex differences in brain structure and function are widespread (Jazin and Cahill, 2010) and analysis of their functional significance has become a priority in the neurosciences (Clayton and Collins, 2014). Interestingly, these sex differences also affect rapid brain estrogen effects (Krentzel and Remage-Healey, 2015). Blocking brain estrogen action/synthesis decreases male sexual motivation within minutes without affecting sexual performance in quail (Seredynski et al., 2013). Here we confirm that blockade of brain aromatase acutely and robustly alters male sexual motivation. This effect is prevented within 15 min by a central injection of E2 or a specific agonist of ERβ, but not of ERα. Furthermore, E2 cannot restore this behavior when mGluR1a is blocked. Together with the previous demonstration that these effects are membrane initiated (Seredynski et al., 2013), the acute modulation of sexual motivation by E2 thus seems to depend on its binding to membrane ERβ, leading to the ...
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Our research group studies the quantitative and molecular genetics of sexual behaviour in the zebra finch to address fundamental questions in evolutionary biology. One of our main interests lies in the understanding of genes that contribute to sexually antagonistic evolution. For instance, we ask, what are the effects of genes that increase male promiscuity (and hence male fitness), on female promiscuity, female fecundity, but also on male and female parental qualities. These and many other questions are addressed using long term data on a very large captive population of zebra finches. Extensive observational data on extra-pair courtships in a communal aviary setting are complemented with breeding of selection lines and large-scale SNP genotyping that allows us to conduct QTL mapping and subsequent study of candidate genes involved the behaviours that lie at the core of sexual selection ...
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The effect of neonatally administered testosterone propionate (TP) on sexual receptivity and fertility was studied. Dosages of 25 μg and ten μg were used and were administered s.c. in peanut oil on the fifth day of life. Vaginal smears of the animals receiving 25 μg were begun at the age of 61 days and indicated that these animals exhibited modified estrous cycles. By 90 days of age, most of the animals in both dosage groups were in constant vaginal estrus. These prolonged periods of vaginal estrus were often interrupted only by mating. At 97 days of age 40 females which received ten μg of TP were caged individually with males for six nights and 40% mated. At this same dose, out of 128 exposures, 42% of the females bred when exposed to males for one night. The latter group received 15 I.U. of chorionic gonadotropin (HCG) on the day of mating. In females receiving 25 μg of TP, out of 481 exposures, 33.6% of the animals mated. Eighty-nine per cent of the females which copulated had a vaginal smear
Waxman AR, Juni A, Kowalczyk W, Arout C, Sternberg WF, Kest B (2010). Progesterone rapidly recruits female-typical opioid-induced hyperalgesic mechanisms. Physiology and Behavior, 101(5), 759-763.. ...
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Recent studies show early exposure to BPA can change male behavior in adulthood. Male mice showed less masculine behavior (less territorial marking).
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Remarkably, we have actually kind of obtained a similar result in one of our previous study (Svensson et al. 2006 Evolution), where we found that strong divergent sexual selection was accompanied by a significant decrease of female response towards conspecifics from other populations. This is corroborated by another study yet from our group, that found reduced gene flow between some of these populations (Svensson et al. 2004 Heredity), like it has been found in other systems (Rice and Pfennig 2010). I had myself never really thought about it that way, and this opened my mind a lot I must say on what Erik and others of our group have done in the past. And what about learning then? Well, we know it is likely to play an important role in divergence of mate preferences in our system (Svensson et al. 2010 Evolution), and all things considered it might even facilitate this process, as mate choice may change faster and thus the constraining effects of gene flow in the early stages will then not be an ...
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In Chapter 9, Darwin in Denial, author Tim Birkhead explains how Darwins failure to recognize avian female promiscuity resulted in a century of misconceptions about sexual selection. 0 Comments. ...
by Vetscite. It may be hard to imagine competing over who gets to kiss a frog, but when it comes to mating, a new study concludes that some frogs have moved out of the pond onto land to make it easier for the male in the pair to give sexual rivals the slip.. Biologists have long thought that some frog species evolved to mate on land - sometimes in unusual places - instead of in open water to better guard eggs and tadpoles from easily being eaten by fish and other predators. But the new research by a team of U.S. and Brazilian frog biologists suggests that mating on land in many species might in part be a strategy that male frogs use to ensure that their own DNA gets passed on, instead of the DNA of their rivals. Sexual selection may trump natural selection in the evolution of these reproductive behaviors, according to the new study, to be published online ahead of print on July 26 in The American Naturalist.. Frogs have a dizzying array of reproductive strategies, according to Rayna Camille ...
The analysis of all of those components together forms part of the new discipline of Systems Biology. Systems biologists study, among other things, the phenomenon of emergence, whereby properties, functions and behaviors of living systems arise though not exhibited by any individual component of the system, and not explainable or predictable from complete understanding the components properties/behaviors considered in isolation from the system that embeds them. Every cellular system exhibits emergent behaviors. Emergent behaviors of living systems include such things as locomotion, sexual display, flocking, and conscious experiencing. Even the biological components of living cells, such as mitochondria and other organelles, exhibit emergent properties. Some biologists might find it tempting to see a type of vitalism, or life force, in living systems, given that some whole-system properties/behaviors of organisms, including even the activity of living itself, exemplify such emergent ...
Get information, facts, and pictures about secondary sexual character at Encyclopedia.com. Make research projects and school reports about secondary sexual character easy with credible articles from our FREE, online encyclopedia and dictionary.
Reproduction and immunity are fitness-related traits that trade-off with each other. Parasite-mediated theories of sexual selection suggest, however, that higher-quality males should suffer smaller costs to reproduction-related traits and behaviours (e.g., sexual display) from an immune challenge because these males possess more resources with which to deal with the challenge. We used Gryllus texensis field crickets to test the prediction that attractive males should better maintain the performance of fitness-related traits (e.g., calling effort) in the face of an immune challenge compared with unattractive males. We found no support for our original predictions. However, that immune activation causes attractive males to significantly increase their calling effort compared with unattractive males suggests that these males might terminally invest in order to compensate for decreased future reproduction.
A large number of studies have analyzed social and sexual interactions between rodents in relation to neural activity. Computerized video analysis has been successfully used to detect numerous behaviors quickly and objectively; however, to date only 2D video recording has been used, which cannot determine the 3D locations of animals and encounters difficulties in tracking animals when they are overlapping, e.g., when mounting. To overcome these limitations, we developed a novel 3D video analysis system for examining social and sexual interactions in rats. A 3D image was reconstructed by integrating images captured by multiple depth cameras at different viewpoints. The 3D positions of body parts of the rats were then estimated by fitting skeleton models of the rats to the 3D images using a physics-based fitting algorithm, and various behaviors were recognized based on the spatio-temporal patterns of the 3D movements of the body parts. Comparisons between the data collected by the 3D system and those by
Probably gyne polymorphism is not rare in Cardiocondyla, but undetected in many species because of the small available sample size. It is expressed by strong variation in mesosoma dimensions and weak differences in postocular distance (a result of larger eye size of the flying macrosomatic gynes), whereas other characters are equal. Thus, gyne polymorphism in Cardiocondyla deviates from gyne polymorphism in Leptothorax, Tetramorium, Messor, or Myrmica in which measurements of all body parts differ between micro- and macrogynes. Hence, the use of the terms macro- and microgynes is problematic in Cardiocondyla; instead the terms macro somatic and microsomatic gynes are used here. Gyne polymorphism was observed in Cardiocondyla ulianini (see also Marikovsky & Yakushkin 1974), Cardiocondyla batesii, Cardiocondyla bicoronata, Cardiocondyla nigra, Cardiocondyla elegans, and Cardiocondyla sahlbergi. All these species are inhabitants of Palaearctic deserts, semi deserts or dry steppes and three of them ...
William Caldwell (WC) Young, a founder of behavioral neuroendocrinology, had a career spanning almost forty years. Trained with Carl Moore at The University of Chicago, Young was interested in hormonal influences on behavior, but Moore dissuaded him saying: … the behavior of animals was utterly capricious, unordered by hormonal events, and unrelated to variables of significance to reproductive biology (Goy, 1967). Fortunately, Young ignored Moore and while at Brown University in 1928 studied hormonal modulation of female sexual receptivity. His studies demonstrated that female guinea pig sexual receptivity varied reliably with cyclic changes in ovarian morphology (Young, Dempsey & Myers, 1935; Myers, Young & Dempsey, 1936). Subsequent classic experiments varied the timing and dosages of estrogen and progesterone given to ovariectomized females, demonstrating that female sexual receptivity required sequential estrogen and progesterone treatment (Dempsey, Hertz, & Young, 1936; Collins, et ...
Attractiveness is a major component of sexual selection that is dependent on sexual characteristics, such as pheromone production, which often reflect an individuals fitness and reproductive potential. Aging is a process that results in a steady decline in survival and reproductive output, yet little is known about its effect on specific aspects of attractiveness. In this report we asked how aging impacts pheromone production and sexual attractiveness in Drosophila melanogaster. Evidence suggests that key pheromones in Drosophila are produced as cuticular hydrocarbons (CHC), whose functions in attracting mates and influencing behavior have been widely studied. We employed gas chromatography/mass spectrometry and laser desorption/ionization mass spectrometry to show that the composition of D. melanogaster CHC is significantly affected by aging in both sexes and that these changes are robust to different genetic backgrounds. Aging affected the relative levels of many individual CHC, and it ...
ABSTRACT: The effect of various social environments on sociosexual behavior was examined in six young female cotton-top tamarins (Saguinus oedipus oedipus) and in three established breeding females. Behavioral observations and hormonal samples were collected on young females while they were living with their families, when they were isolated from conspecifics, and after they were paired with an unrelated male. While living with the family, all females showed a suppression of fertility and low frequencies of sociosexual behavior. Following removal from the family, isolated females displayed an increase in rate of scent marking and an increase in hormonal levels. When young females were paired with males, they were exposed to scent secretions from their natal families, from an unfamilar family, and from a control for a total of 24 weeks. After pairing, hormonal levels increased dramatically, and ovarian cyclicity began. An increase in sociosexual behavior and elevated levels of scent marking ...
TY - JOUR. T1 - Coevolution of female ovulatory signals and male-male competition in primates. AU - Nakahashi, Wataru. PY - 2016/3/7. Y1 - 2016/3/7. N2 - Visual signals of ovulation vary among primate species. Although slight ovulatory signals are considered primate ancestral traits of which some species still exhibit, some show prominent swelling of their perineal skin (exaggerated sexual swellings) and others do not exhibit any signals of ovulation (concealed ovulation). These signals strongly affect male mating behaviors. I develop an evolutionary model of female ovulatory signals and male-male competition. I assume that each male allocates his effort between attraction of females and male-male competition for dominance. Each female gains a benefit if she is fertile and free from the alpha male who always guards one of the most fertile females in the group, but suffers a cost if she expresses a different ovulatory signal from an ancestral trait. I show that various types of ovulatory signals ...
Environmental stimulation results in an increased expression of transcription factors called immediate early genes (IEGs) in specific neuronal populations. In male Japanese quail, copulation with a female increases the expression of the IEGs zenk and c-fos in the medial pre-optic nucleus (POM), a key nucleus controlling male sexual behavior. The functional significance of this increased IEG expression that follows performance of copulatory behavior is unknown. We addressed this question by repeatedly quantifying the performance of appetitive (learned social proximity response) and consummatory (actual copulation) sexual behavior in castrated, testosterone-treated males that received daily intra-cerebroventricular injection of an antisense oligodeoxynucleotide targeting c-fos or control vehicle. Daily antisense injections significantly inhibited the expression of copulatory behavior as well as the acquisition of the learned social proximity response. A strong reduction of the proximity response ...
That fru acts during development to establish the potential for male sexual behavior is suggested by the patterns of expression of male-specific P1 products. The FRUM proteins are expressed almost exclusively in the CNS, where they are first detected in a small number of cells at the end of the larval period. Expression is maximal about two days into the pupal period when ca. 1700 cells (2% of the CNS) express FRUM proteins; this time coincides with the period of major morphogenetic events that shape the adult CNS (Figure 1). Cells expressing the FRUM proteins are not localized to one part of the CNS. They are scattered throughout the brain and VNC, most frequently found in small groups of cells, and less frequently as single cells. There are approximately 20 groups of FRUM neurons (Fig. 2). Some of these groups are in specific regions of the CNS previously shown to be involved in particular steps of courtship behavior. In addition, a number of regions containing FRUM neurons had not been ...
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In ecological character displacement, traits involved in reproductive isolation may not evolve in arbitrary directions when changes in these traits are by-products of adaptation to an ecological niche. In reproductive character displacement, however, selection acts directly on reproductive characters to enhance the degree of reproductive isolation between sympatric populations. Thus, the direction of change in reproductive characters may be arbitrary in relation to changes in other morphological characters. We characterized both tegminal characters and characters indicative of body size in sympatric and allopatric populations of Gryllus fultoni, a species displaying character displacement in its calling song characters in areas of sympatry with G. vernalis populations, to infer the nature and direction of selection acting on reproductive and morphological characters in sympatry. Except for mirror area, the number of teeth in a file, and ovipositor length of G. fultoni, all male and female morphological
The controversy engendered by this first book caused Kinseys second book, Sexual Behavior in the Human Female, to be eagerly anticipated by his critics, his defenders, the media, and the public. Its publication in was met with an equal if not greater storm than the publication of the book on men.3/5(15).. Statistical problems of the Kinsey report on sexual behavior in the human male;: Statistical problems of the Kinsey report on sexual behavior in the human male book report of the American Statistical Association, Committee to advise Committee for Research in Problems of Sex, [Cochran, William Gemmell] on *FREE* shipping on qualifying offers.. Statistical problems of the Kinsey report on sexual behavior in the human male;: A report of the American Statistical Author: William Gemmell Cochran. Get this from a library. Statistical problems of the Kinsey report on sexual behavior in the human male: a report of the American Statistical Association committee to advise the National Research Council, ...
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Precise estimates of costs and benefits, the fitness economics, of mating are of key importance in understanding how selection shapes the coevolution of male and female mating traits. However, fitness is difficult to define and quantify. Here, we used a novel application of an established analytical technique to calculate individual- and population-based estimates of fitness-including those sensitive to the timing of reproduction-to measure the effects on females of increased exposure to males. Drosophila melanogaster females were exposed to high and low frequencies of contact with males, and life-history traits for each individual female were recorded. We then compared different fitness estimates to determine which of them best described the changes in life histories. We predicted that rate-sensitive estimates would be more accurate, as mating influences the rate of offspring production in this species. The results supported this prediction. Increased exposure to males led to significantly ...
In rodents, sexual behavior depends on the adequate detection of sexually relevant stimuli. The olfactory bulb (OB) is a region of the adult mammalian brain undergoing constant cell renewal by continuous integration of new granular and periglomerular neurons in the accessory (AOB) and main (MOB) olfactory bulbs. The proliferation, migration, survival, maturation, and integration of these new cells to the OB depend on the stimulus that the subjects received. We have previously shown that 15 days after females control (paced) the sexual interaction an increase in the number of cells is observed in the AOB. No changes are observed in the number of cells when females are not allowed to control the sexual interaction. In the present study we investigated if in male rats sexual behavior increases the number of new cells in the OB. Male rats were divided in five groups: 1) males that did not receive any sexual stimulation, 2) males that were exposed to female odors, 3) males that mated for 1 h and could not
Most single-species population models assume either that one sex dominates the growth dynamics (usually the female), or that the life cycles of the two sexes are identical; however, sexual differences in ontogenetic features can render this assumption invalid. Further, the interaction between sexes is necessarily nonlinear, and the dependence of dynamic behavior on sexual interactions can be complicated. Here we examine a two-sex population model, related to the well-known logistic model, with explicit sexual interactions. The model is bistable and, by the addition of diffusion, admits traveling wave solutions. Dominance of states via this spatial dynamic are examined. A simple condition for neutral dominance is obtained; sexual interactions inhibit the dominance of the nonzero population, making persistence more difficult.
In Drosophila ananassae, artificial selection was carried out for fast and slow remating speed for 10 generations. Response to selection resulted in rapid divergence in remating time in each of two replicates of both fast and slow lines. There were significant differences in mean remat-ing time in females among fast, slow, and control lines. Regression coefficients for both fast and slow lines are significantly different from zero. The realized heritability over 10 genera-tions of selection is from 0.26 to 0.33 for two replicates of fast line and from 0.23 to 0.27 for two replicates of slow line. These findings suggest that female remating time in D. ananassae is under polygenic control. Remating frequency of females showed a correlated response in both fast and slow lines. At generation 10, correlated response to selection was also investigated. Mating propensity of D. ananassae of fast and slow lines was observed in an Elens-Wattiaux mating chamber. Fifteen pairs per test showed that on the ...
The ventromedial hypothalamus (VMH) plays a central role in the regulation of the female reproductive behavior lordosis, a behavior dependent upon the sequential activation of receptors for the ovarian steroid hormones estradiol (E) and progesterone (P). These receptors function as transcription factors to alter the expression of target genes. To discover behaviorally relevant genes targeted by E and P in the VMH, we used the differential display PCR to identify messenger RNAs that are differentially expressed in the hypothalamus of ovariectomized (ovx) rats treated with E alone compared with ovariectomized rats treated with E and P. We show here that one interesting mRNA within the hypothalamus that is repressed by P after E priming encodes the protein 25-Dx, the rat homolog of the human membrane-associated P-binding protein Hpr6.6. Neurons in the brain containing the highest levels of 25-Dx are located in several nuclei of the basal forebrain, including the VMH. 25-Dx expression is also higher ...
Female mammals appear to evolve promiscuity as a defence against infanticide by dominant males, and this in turn swells the males testicles
Background. The genetic benefits of mate choice are limited by the degree to which male and female fitness are genetically correlated. If the intersexual correlation for fitness is small or negative, choosing a highly fit mate does not necessarily result in high fitness offspring.. Methodology/Principal Finding. Using an animal-model approach on data from a pedigreed population of over 7,000 collared flycatchers (Ficedula albicollis), we estimate the intersexual genetic correlation in Lifetime Reproductive Success (LRS) in a natural population to be negative in sign (−0.85±0.6). Simulations show this estimate to be robust in sign to the effects of extra-pair parentage. The genetic benefits in this population are further limited by a low level of genetic variation for fitness in males.. Conclusions/Significance. The potential for indirect sexual selection is nullified by sexual antagonistic fitness effects in this natural population. Our findings and the scarce evidence from other studies ...
VIDAL MALDONADO, Marcela. A. Eye orbit geometric shape in Liolaemus as an indicator of polygyny or monogamy. Gayana (Concepc.) [online]. 2011, vol.75, n.2, pp.155-160. ISSN 0717-6538. http://dx.doi.org/10.4067/S0717-65382011000200004.. Most animal groups have sexual dimorphism in morphological characters, especially body size. In many cases, sexual dimorphism may be a consequence of a hierarchical social organization within populations. However, polygyny or monogamy may evolve independently of sexual dimorphism. Two Liolaemus species are known to be good model species to study the relationship between sexual dimorphism and sexual social system: Liolaemus tenuis (polygyny) and Liolaemus copiapoensis (monogamy). In this study, I evaluate the morphological variation in the geometric shape of the orbit between sexes in the two species, comparing their social condition (polygyny, monogamy) and applying a geometric morphometrical methodology. The results show morphological differentiation in orbit ...
In field and laboratory studies of birds, positive associations between male phenotype and success at obtaining extra-pair copulations or extra pair fertilizations are often interpreted as providing evidence that females are using extra-pair copulations to obtain indirect benefits for their offspring, either through genes for increased viability, or for a fisherian mating advantage. I describe a simple model, in which functional fertility (the success of ejaculates in fertilizing eggs) covaries with male phenotype, which can explain the observed associations equally well. Under such a model, females pursue extra-pair copulations as insurance against the functional infertility of their mate, and obtain only direct benefits for themselves in their current reproductive event. Several studies of birds suggest that a relation between male phenotype and functional fertility is often likely to exist and that there are many potential causes of functional infertility. Non-manipulative field studies are unlikely
Currently, I am a Postdoctoral Research Associate in the Department of Biological Sciences and the Eck Instititue for Global Health at the University of Notre Dame. The Severson Lab studies the genetics and genomics of mosquitoes that transmit human diseases. I study genetic mechanisms that underlie complex traits associated with bloodfeeding in Culex pipiens and Aedes aegypti. West Nile Virus is just one disease transmitted by the Culex pipiens complex and Aedes aegypti is a vector of multiple neglected tropical diseases including Dengue and Chikungunya. As no vaccine exists for these diseases, transmission is prevented through mosquito control. A more complete understanding of the genes and genetic pathways that regulate female reproductive behaviors will inform development and implementation of vector control methods. Our ability to generate informative genetic markers (SNPs) and infer quantitative trait loci (QTL) has increased dramatically with the advent of massively parallel sequencing ...
Currently, I am a Postdoctoral Research Associate in the Department of Biological Sciences and the Eck Instititue for Global Health at the University of Notre Dame. The Severson Lab studies the genetics and genomics of mosquitoes that transmit human diseases. I study genetic mechanisms that underlie complex traits associated with bloodfeeding in Culex pipiens and Aedes aegypti. West Nile Virus is just one disease transmitted by the Culex pipiens complex and Aedes aegypti is a vector of multiple neglected tropical diseases including Dengue and Chikungunya. As no vaccine exists for these diseases, transmission is prevented through mosquito control. A more complete understanding of the genes and genetic pathways that regulate female reproductive behaviors will inform development and implementation of vector control methods. Our ability to generate informative genetic markers (SNPs) and infer quantitative trait loci (QTL) has increased dramatically with the advent of massively parallel sequencing ...
In addition to aggressive contexts, many fishes produce water movements that could be used as mechanosensory signals during their courtship repertoire. For example, body quivers, in which males display and vibrate their bodies while in close proximity to a female, are a common courtship behavior. Furthermore, some male fish produce tail waggles to encourage a sexually receptive female to spawn. Male three-spined sticklebacks (Gasterosteus aculeatus) use a zig-zag dance to court gravid females (Tinbergen, 1951; Tinbergen and Van Iersel, 1947), and in many species of wrasses, terminal-phase (i.e. dominant, territory-holding and reproductively competent) males combine intense body vibrations with rapid tail beats while swimming back and forth over a potential mate (Robertson and Hoffman, 1977). Despite the obvious use of hydrodynamic signal-generating behaviors, only a few studies have examined the role of mechanosensation during reproductive encounters. Because any signals produced during ...
Fingerprint Dive into the research topics of Topography in the preoptic region: Differential regulation of appetitive and consummatory male sexual behaviors. Together they form a unique fingerprint. ...
Colour signals play a pivotal role in sexual selection (for review see Andersson 1994; Whiting et al. 2003). Of particular recent interest are ultraviolet (UV; 300-400 nm) signals, which are invisible to the human eye. In some taxa, UV signals are used by females to assess mates (e.g. Andersson et al. 1998; Johnsen et al. 1998; Siitari et al. 2002), but few studies have considered how UV signals are used during male contest competition (Alonso-Alvarez et al. 2004; Siebeck 2004; Siefferman & Hill 2005; Whiting et al. in press). Male traits such as colour, body size, and alternative reproductive tactics (ART; territorial and floater) are the most consistent and widespread predictors of aggressive behaviour and contest outcome (Neat et al. 1998; Johnsson & Forser 2002; Kemp & Wiklund 2004); however, few studies disentangle their roles (Qvarnstrom 1997; Pryke & Andersson 2003) and none have considered how UV may interact with body size and residency to influence rival assessment and contest outcome. ...
Mating strategies vary between species, populations, individuals, and even within an individual. For instance, an individual might use different strategies to maximise its fitness when it is old, compared to when it is young. In most bird species, both females and males engage in copulations outside their pair bond (extra-pair copulations). Extra-pair males are commonly older males. However, whether older males get better at outcompeting younger rivals (the observed effect takes place within an individual) or are simply the ones that live longest (the observed effect arises through cross-sectional comparison between individuals) remains to be clarified. In my PhD, I use an experimental breeding design in a captive population of house sparrows, as well as a long-term dataset from a wild population to study the occurrence of extra-pair offspring and its interaction with parental age. I compare the fitness of within- and extra-pair offspring associated with parental age, quantify fitness ...
By Melinda Carstensen Published October 10, 2014 FoxNews.com Previous research shows that the hormone oxytocin stimulates social behavior in humans, but a study published Thursday in the journal Cell suggests the hormone plays an especially strong role in regulating female sexual behavior. Scientists at The Rockefeller University in New York City genetically modified female mice…
Greenwood, A. W. andCrew, F. A. E. (1926). Studies on the Relation of Gonadic Structure to Plumage in the Domestic Fowl. I. Heuny Feathering in an Ovariotomised Hen with an Active Teatis Graft.P.R.S. B, XCIX, 232-249.. ...
Asymmetries in courtship signals can result from both developmental instability during ontogeny and from temporary or permanent damage following mating, fighting, or interactions with predators. These two types of asymmetries, which can be divided into fluctuating asymmetry (FA) and damage asymmetry (DA), have both been suggested to play an important role in mate choice as potential honest indicators of phenotypic and/or genetic quality, while at the same time, DA may affect ornament asymmetry in a random manner. Interestingly, despite the massive research effort that has been devoted to the study of asymmetry during the past decades, very little is known about how an individuals behaviour relates to asymmetry. Here, we measure and characterise asymmetry in morphological courtship signals in Corynopoma riisei, a fish where males carry elaborate paddle-like appendices on each side of the body that they display in front of females during courtship. Moreover, we investigate whether male courtship ...
Male [I]Drosophila subobscura[/I] courtship behavior is composed of tapping, scissoring, proboscis extension, midleg swing, nuptial gift, dance, wing extension and attempted copulation.
For more information on Caregivers Response to Sex Play, click here.. What are some diagnostic considerations for professionals? Problematic sexual behaviors are not a diagnosable condition. Rather, these behaviors are clinically concerning behaviors. At times, the problematic sexual behaviors represent an isolated problem of a child who is otherwise functioning well. Other times, the sexual behaviors may be part of a pattern of disruptive or delinquent behaviors. Some children with problematic sexual behaviors have also experienced trauma, and the problematic sexual behaviors may be one of the symptoms related to the trauma. The following section provides guidance for diagnostic consideration, as well as more information about specific diagnoses: American Psychiatric Association Diagnostic and Statistical Manual.. What do I need to know about problematic sexual behaviors as an isolated problem?. Problematic sexual behaviors may be an isolated problem. This is more often the case with older ...
Animals perform or terminate particular behaviors by integrating external cues and internal states through neural circuits. Identifying neural substrates and their molecular modulators promoting or inhibiting animal behaviors are key steps to understand how neural circuits control behaviors. Here, we identify the Cholecystokinin-like peptide Drosulfakinin (DSK) that functions at single-neuron resolution to suppress male sexual behavior in Drosophila. We found that Dsk neurons physiologically interact with male-specific P1 neurons, part of a command center for male sexual behaviors, and function oppositely to regulate multiple arousal-related behaviors including sex, sleep and spontaneous walking. We further found that the DSK-2 peptide functions through its receptor CCKLR-17D3 to suppress sexual behaviors in flies. Such a neuropeptide circuit largely overlaps with the fruitless-expressing neural circuit that governs most aspects of male sexual behaviors. Thus DSK/CCKLR signaling in the sex ...