Links for Keyword: Sexual Behavior

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Morwenna Ferrier Is my face attractive? Don’t answer that. Not because I’m ducking out of this, but because you can’t. Attractiveness is subjective, perhaps the most subjective question of all; that we outsource the answer to Google (and we do, in our droves) is ironic since it depends on a bias that is impossible to unpack. Yet in searching the internet for an answer, it also reveals the question to be one of the great existential tensions of our time. Because, as we all know, being attractive is absolutely 100% the A-road to happiness. If you are Googling to rate your attractiveness, then you are probably working on the assumption that you aren’t. You’re also, possibly, more vulnerable and susceptible to being told that you aren’t. In short, you’re a sitting duck, someone who had a sore throat and who asked good old Dr Google for advice only to be told it was cancer. Still, it’s only in investigating precisely why Google is the last person you should ask – being a search engine therefore insentient – that you can start cobbling together an idea of what attractiveness really is. It’s worth starting with semantics. Beauty is not attractiveness and vice versa, though we commonly confuse the two. Beauty (arguably) has a template against which we intuit and against which we measure ourselves. It is hinged around genetics and a particular look associated with this politically correct (and largely western-governed) model. Darwin wouldn’t agree: “It is certainly not true that there is in the mind of man any universal standards of beauty with respect to the human body,” he said. But a lot has changed since his time. © 2016 Guardian News and Media Limited

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 23030 - Posted: 12.28.2016

Laura Sanders Pregnancy changes nearly everything about an expectant mother’s life. That includes her brain. Pregnancy selectively shrinks gray matter to make a mom’s brain more responsive to her baby, and those changes last for years, scientists report online December 19 in Nature Neuroscience. “This study, coupled with others, suggests that a women’s reproductive history can have long-lasting, possibly permanent changes to her brain health,” says neuroscientist Liisa Galea of the University of British Columbia in Vancouver, who was not involved in the study. Researchers performed detailed anatomy scans of the brains of 25 women who wanted to get pregnant with their first child. More scans were performed about two months after the women gave birth. Pregnancy left signatures so strong that researchers could predict whether women had been pregnant based on the changes in their brains. The women who had carried a child and given birth had less gray matter in certain regions of their brains compared with 20 women who had not been pregnant, 19 first-time fathers and 17 childless men. These changes were still evident two years after pregnancy. A shrinking brain sounds bad, but “reductions in gray matter are not necessarily a bad thing,” says study coauthor Elseline Hoekzema, a neuroscientist at Leiden University in the Netherlands. A similar reduction happens during adolescence, a refinement that is “essential for a normal cognitive and emotional development,” says Hoekzema, who, along with colleagues, did most of the work at Universitat Autònoma de Barcelona. Following those important teenage years, pregnancy could be thought of almost as a second stage of brain maturing, she says. |© Society for Science & the Public 2000 - 2016.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 23002 - Posted: 12.20.2016

By Claire Asher We pride ourselves on our big brains, but when it comes to figuring out whether people or other animals with particularly big brains do better than others, the evidence has been lacking. Now, for the first time, a study in red deer is showing that bigger brained mammals tend to be more successful in the wild, and that brain size is a heritable trait that they can pass on to their offspring. Corina Logan from the University of Cambridge and her team have looked at the skulls of 1314 red deer (Cervus elaphus) from the Isle of Rum. The complete life histories of the deer are well known thanks to the Isle of Rum Red Deer Project, which has been collecting data on the island for more than 40 years, spanning seven deer generations. “This kind of study has not been conducted before because it requires long-term data from a large number of individuals,” says Logan. Heritable heads The team found that the ratio of skull volume to body size was highly heritable, explaining 63 per cent of variation between individuals. Female deer with larger skulls lived significantly longer and raised more offspring to adulthood, though it’s not clear yet why bigger brains are advantageous to females. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22987 - Posted: 12.14.2016

By Sam Wong Size matters. Bigger genitals mean more mating success for male mosquito fish, a relative of the guppy. But the development of longer male organs prompts females to evolve bigger brains to help them escape overeager mates. Mating among mosquito fish is far from romantic. The male makes no effort to court partners, instead sneaking up and attempting to copulate by force up to a thousand times a day. It uses a modified anal fin, the gonopodium, to deliver sperm into the female. In this sort of mating system, the relationship between males and females can resemble that between predators and prey, which commonly involve an evolutionary arms race where adaptations on one side are closely matched by changes on the other. For example, big-brained predators tend to prey on big-brained prey, as the two try to outsmart each other. Séverine Buechel and colleagues at Stockholm University in Sweden wondered if a similar arms race was going on between male and female mosquito fish. Do females evolve bigger brains to defend against sneaky males, and do males evolve bigger brains in response? To test this, the team looked at what happened to brain size when males were bred to have longer gonopodia. Male mosquito fish have long gonopodia compared with related species in which coercion is not the dominant mating strategy, and males with longer gonopodia tend to be more successful at mating. The researchers found that breeding more well-endowed males led to bigger-brained females. But there was no arms race: male brains didn’t get bigger at the same time. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22973 - Posted: 12.10.2016

Barbara J. King Birdsong is music to human ears. It has inspired famous composers. For the rest of us, it may uplift the spirit and improve attention or simply be a source of delight, fun and learning. But have you ever wondered what birds themselves hear when they sing? After all, we know that other animals' perceptions don't always match ours. Anyone who lives with a dog has probably experienced their incredible acute hearing and smell. Psychologists Robert J. Dooling and Nora H. Prior think they've found an answer to that question — for, at least, some birds. In an article published online last month in the journal Animal Behaviour, they conclude that "there is an acoustic richness in bird vocalizations that is available to birds but likely out of reach for human listeners." Dooling and Prior explain that most scientific investigations of birdsong focus on things like pitch, tempo, complexity, structural organization and the presence of stereotypy. They instead focused on what's called temporal fine structure and its perception by zebra finches. Temporal fine structure, they write, "is generally defined as rapid variations in amplitude within the more slowly varying envelope of sound." Struggling to fully grasp that definition, I contacted Robert Dooling by email. In his response, he suggested that I think of temporal fine structure as "roughly the difference between voices when they are the same pitch and loudness." Temporal fine structure is akin, then, to timbre, sometimes defined as "tone color" or, in Dooling's words, the feature that's "left between two complex sounds when the pitch and level are equalized." © 2016 npr

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 8: Hormones and Sex
Link ID: 22942 - Posted: 12.03.2016

By Clare Wilson Could a brain stimulation device change our sex drive? The first study of this approach suggests that people’s libido can be turned up or down, depending on the device’s setting. The study didn’t measure how much sex people had in real life, instead it measured participant’s sexual responsiveness. Unusually, this was done by fixing customised vibrators to people’s genitals and gauging how their brainwaves changed when they expected a stimulating buzz. “You want to see if they want what you’re offering,” says Nicole Prause at the University of California, Los Angeles. “This is a good model for sexual desire.” The technique involves transcranial magnetic stimulation (TMS), where a paddle held above the head uses a strong magnetic field to alter brain activity. It can be used to treat depression and migraines, and is being investigated for other uses, including preventing bed-wetting, and helping those with dyslexia. The part of the head targeted in this study – called the left dorsolateral prefrontal cortex, roughly above the left temple – is involved in the brain’s reward circuitry. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22936 - Posted: 12.01.2016

Carrie Arnold There was one sound that biologist Rusty Gonser always heard at Cranberry Lake — and there was one sound that he would never hear again. Every summer for more than 25 years, Gonser and his wife, Elaina Tuttle, had made the trip to this field station in the Adirondack Mountains — a 45-minute boat ride from the nearest road. Now, as he moored his boat to the shaky wooden dock, he heard a familiar and short song that sounded like 'oh-sweet-Canada'. The whistle was from a white-throated sparrow calling hopefully for a mate. What he didn't hear was the voice or laughter of his wife. For the first time, Gonser was at Cranberry Lake alone. Just a few weeks earlier, Tuttle had died of breast cancer. Her entire career, and most of Gonser's, had been devoted to understanding every aspect of the biology of the white-throated sparrow (Zonotrichia albicollis). Less than six months before she died this year at the age of 52, the couple and their team published a paper1 that was the culmination of that work. It explained how a chance genetic mutation had put the species on an extraordinary evolutionary path. The mutation had flipped a large section of chromosome 2, leaving it unable to pair up with a partner and exchange genetic information. The more than 1,100 genes in the inversion were inherited together as part of a massive 'supergene' and eventually drove the evolution of two different 'morphs' — subtypes of the bird that are coloured differently, behave differently and mate only with the opposite morph. Tuttle and Gonser's leap was to show that this process is nearly identical to the early evolution of certain sex chromosomes, including the human X and Y. The researchers realized that they were effectively watching the bird evolve two sex chromosomes, on top of the two it already had. © 2016 Macmillan Publishers Limited,

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22900 - Posted: 11.23.2016

By Solomon Israel, A May-December romance brings benefits for young female gray jays mated to older males, according to new Canadian research. The paper, published this month in the journal Animal Behaviour, used almost four decades of data on a marked population of gray jays in Ontario's Algonquin Park to study how the birds adjust their reproductive habits in response to changes in temperature and other conditions. Gray jays, also known as Canada jays or whisky jacks, don't migrate south in the winter, instead living year-round in boreal forests across Canada and the northern U.S. They manage this feat of survival by caching food all over their large, permanent habitats, then retrieving it during the winter months. The small, fluffy birds take advantage of those winter supplies to nest much earlier than most other birds, laying eggs between late February and March. Gray jays don't migrate during the winter, instead relying on hidden caches of food to feed themselves and their offspring. (Dan Strickland) The researchers found that female gray jays that laid their eggs earlier in the season had the most reproductive success, with a higher survival rate for offspring. ©2016 CBC/Radio-Canada

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22836 - Posted: 11.07.2016

Susan Milius For widemouthed, musical midshipman fish, melatonin is not a sleep hormone — it’s a serenade starter. In breeding season, male plainfin midshipman fish (Porichthys notatus) spend their nights singing — if that’s the word for hours of sustained foghorn hums. Males dig trysting nests under rocks along much of North America’s Pacific coast, then await females drawn in by the crooning. New lab tests show that melatonin, familiar to humans as a possible sleep aid, is a serenade “go” signal, says behavioral neurobiologist Ni Feng of Yale University. From fish to folks, nighttime release of melatonin helps coordinate bodily timekeeping and orchestrate after-dark biology. The fish courtship chorus, however, is the first example of the hormone prompting a launch into song, according to Andrew Bass of Cornell University. And what remarkable vocalizing it is. The plainfin midshipman male creates a steady “mmm” by quick-twitching specialized muscles around its air-filled swim bladder up to 100 times per second in chilly water. A fish can extend a single hum for about two hours, Feng and Bass report October 10 in Current Biology. That same kind of super-fast muscle shakes rattle-snake tails and trills vocal structures in songbirds and bats. |© Society for Science & the Public 2000 - 2016

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 10: Biological Rhythms and Sleep
Link ID: 22767 - Posted: 10.19.2016

By Christian Jarrett It’s been said that men and women are so unlike each other, it’s as if they’re from different planets – a claim that continues to amuse and irritate. John Gray’s original mega-selling book Men are from Mars, Women are from Venus, first published in the early 1990s, has sold millions, spawning numerous parodies (such as Katherine Black and Finn Contini’s Women May Be from Venus, But Men are Really from Uranus) and even comedy stage shows, such as Men are from Mars, Women are from Venus, Live! currently playing off Broadway.) While our physical differences in size and anatomy are obvious, the question of psychological differences between the genders is a lot more complicated and controversial. There are issues around how to reliably measure the differences. And when psychologists find them, there are usually arguments over whether the causes are innate and biological, or social and cultural. Are men and women born different or does society shape them that way? These questions are particularly thorny when you consider our differences in personality. Most research suggests that men and women really do differ on some important traits. But are these differences the result of biology or cultural pressures? And just how meaningful are they in the real world? One possibility is that most differences are tiny in size but that combined they can have important consequences. One of the most influential studies in the field, published in 2001 by pioneering personality researchers Paul Costa, Robert McCrae and Antonio Terracciano, involved over 23,000 men and women from 26 cultures filling out personality questionnaires. © 2016 BBC.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22746 - Posted: 10.12.2016

Susan Milius ORLANDO, Fla. — When sex chromosomes among common pill bugs go bad from disuse, borrowed bacterial DNA comes to the rescue. Certain pill bugs grow up female because of sex chromosomes cobbled together with genes that jumped from the bacteria. Genetic analysis traces this female-maker DNA to Wolbachia bacteria, Richard Cordaux, based at the University of Poitiers with France’s scientific research center CNRS, announced September 29 at the International Congress of Entomology. Various kinds of Wolbachia infect many arthropods, spreading from mother to offspring and often biasing their hosts’ sex ratios toward females (and thus creating even more female offspring). In the common pill bug (Armadillidium vulgare), Wolbachia can favor female development two ways. Just by bacterial infection without any gene transfer, bacteria passed down to eggs can make genetic males develop into functional females. Generations of Wolbachia infections determining sex let these pill bugs’ now-obsolete female-making genes degenerate. Which makes it very strange that certain populations of pill bugs with no current Wolbachia infection still produce abundant females. That’s where Cordaux and Poitier colleague Clément Gilbert have demonstrated a second way that Wolbachia makes lady pill bugs — by donating DNA directly to the pill bug genes. The researchers, who share an interest in sex determination, have built a case that Wolbachia inserted feminizing genes into pill bug chromosomes. The bacterial genes thus created a new sex chromosome. 5|© Society for Science & the Public 2000 - 2016

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22717 - Posted: 10.02.2016

By Jessica Boddy Activity trackers like Fitbits and Jawbones help fitness enthusiasts log the calories they burn, their heart rates, and even how many flights of stairs they climb in a day. Biologist Cory Williams of Northern Arizona University in Flagstaff is using similar technology to track the energy consumption of arctic ground squirrels in Alaska—insight that may reveal how the animals efficiently forage for food while avoiding being picked off by golden eagles. This week, Williams published a study in Royal Society Open Science that compared the activity levels of male and female squirrels. He found that although males spend a lot more time outside of their burrows, they’re pretty lazy, and sometimes just bask in the sun during warmer months. Females, on the other hand, have limited time to spare when caring for their young, and use it to run around and forage for themselves and their babies. In addition to previous work on arctic ground squirrel hibernation and seasonal differences in behavior, the finding is helping his team figure out why males tend to be more susceptible to being eaten. Williams sat down with Science to talk about creating a squirrel Fitbit, catching the animals in the wild, and how technology is improving ecological research. This interview has been edited for brevity and clarity. Q: What got you interested in studying arctic ground squirrels? A: It’s one of the only arctic animals that keeps a rigid schedule even when there’s no light/dark cycle for 6 week—meaning, they emerge from and return to their burrows the same time every day and they eat the same time each day, even though the sun stays in the sky for weeks and weeks. So I started to deploy the energy tracking technologies to better understand how the squirrels use energy through the seasons. © 2016 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 5: The Sensorimotor System
Link ID: 22714 - Posted: 09.30.2016

By Clare Wilson IT HAS been blamed for brain shrinkage, impotence, divorce and paedophilia – and in April this year, Utah declared it a public health hazard. Warnings about pornography come not just from religious or conservative groups – former Playboy model and actor Pamela Anderson also recently cautioned against its “corrosive effects”. Yet survey after survey shows porn use is common among men and not exactly rare in women, so can it really be so dangerous? Or could it even have benefits? While there is research into the effects of porn, a great deal of it is contradictory. Even the same studies are interpreted differently by those on opposite sides of the debate. Some feel it is a menace to society, while others think that attitude belongs with 1980s hysteria over video nasties. Anti-porn campaigners chiefly argue that it is addictive and hijacks the brain’s normal reward pathways. Like heroin addicts who crave more of their drug to get the same high, users find they are no longer aroused by real sex and resort to increasingly harder-core material, or so the theory goes. Of course, there are other concerns over pornography, such as its depictions of violence, exploitation and sexual consent. But male addiction is an increasing focus of anti-porn campaigns. Campaigners say that an excess of porn prompts users to spurn their partners and seek out images of bestiality, rape scenes, and child abuse. Some schools in Scotland now warn that viewing adult images leads to impotence, coercion and abuse. “This kind of escalation is described over and over again,” says Gary Wilson, a retired biology lecturer and author of website and book Your Brain on Porn. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22706 - Posted: 09.29.2016

By Karl Gruber Five lionesses in Botswana have grown a mane and are showing male-like behaviours. One is even roaring and mounting other females. Male lions are distinguished by their mane, which they use to attract females, and they roar to protect their territory or call upon members of their pride. Females lack a mane and are not as vocal. . New Scientist Live: Book tickets to our festival of ideas and discovery – 22 to 25 September in London But sometimes lionesses grow a mane and even behave a bit like males. However, until now, reports of such maned lionesses have been extremely rare and largely anecdotal. We knew they existed, but little about how they behave. Now, Geoffrey D. Gilfillan at the University of Sussex in Falmer, UK, and colleagues have reported five lionesses sporting a mane at the Moremi Game Reserve in Botswana’s Okavango delta. Gilfillan started studying these lionesses back in March 2014, and for the next two years he focused on recording the behaviour of one of them, called SaF05. She had an underdeveloped mane and was larger than most females. “While SaF05 is mostly female in her behaviour – staying with the pride, mating males – she also has some male behaviours, such as increased scent-marking and roaring, as well as mounting other females,” says Gilfillan. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 11: Emotions, Aggression, and Stress
Link ID: 22687 - Posted: 09.23.2016

By Colin Barras It is not just about speed. The only songbird known to perform a rapid tap dance during courtship makes more noise with its feet during its routines than at other times. The blue-capped cordon-bleu (Uraeginthus cyanocephalus) from East Africa is blessed with the attributes of a Broadway star: striking good looks, a strong singing voice – and fine tap-dancing skills. The dances are so fast that they went unnoticed until 2015, when Masayo Soma at Hokkaido University in Japan and her colleagues captured the performances on high-speed film. The bird’s speciality is a left-right-left shuffle ­– only with the feet striking the perch up to 50 times a second. The vision of some birds operates at a faster rate than that of humans, so the cordon-bleu’s dance may simply be about creating an impressive visual performance. But it could also be about winning over a potential mate with rhythm. To explore the idea, Soma and her colleagues recorded audio of the courtship dances, which both males and females perform. They found that the tap dances are unusually loud: the feet strike the branch with enough force to generate sound averaging 30 decibels. This typically drops to just 20 decibels when a bird’s feet strike the branch as it hops around when it is not performing, which means the step sounds are not just a by-product of movement. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22665 - Posted: 09.19.2016

By Jesse Singal Back in 2014, a bigoted African leader put J. Michael Bailey, a psychologist at Northwestern, in a strange position. Yoweri Museveni, the president of Uganda, had been issuing a series of anti-gay tirades, and — partially fueled by anti-gay religious figures from the U.S. — was considering toughening Uganda’s anti-gay laws. The rhetoric was getting out of control: “The commercialisation of homosexuality is unacceptable,” said Simon Lokodo, Uganda’s ethics minister. “If they were doing it in their own rooms we wouldn’t mind, but when they go for children, that’s not fair. They are beasts of the forest.” Eventually, Museveni said he would table the idea of new legislation until he better understood the science of homosexuality, and agreed to lay off Uganda’s LGBT population if someone could prove to him homosexuality was innate. That’s where Bailey comes in: He’s a leading sex researcher who has published at length on the question of where sexual orientation comes from. LGBT advocates began reaching out to him to explain the science of homosexuality and, presumably, denounce Museveni for his hateful rhetoric. But “I had issues with rushing out a scientific statement that homosexuality is innate,” he said in an email, because he’s not sure that’s quite accurate. While he did write articles, such as an editorial in New Scientist, explaining why he thought Museveni’s position didn’t make sense, he stopped short of calling homosexuality innate. He also realized that in light of some recent advances in the science of sexual orientation, it was time to publish an article summing up the current state of the field — gathering together all that was broadly agreed-upon about the nature and potential origins of sexual orientation. (In the meantime, Museveni did end up signing the anti-gay legislation, justifying his decision by reasoning that homosexuality “was learned and could be unlearned.”) © 2016, New York Media LLC.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 13: Memory, Learning, and Development
Link ID: 22628 - Posted: 09.05.2016

By Christie Aschwanden The Olympic stadium was quiet on Wednesday morning, and spectators in the sparsely filled stands seemed to pay little notice to South African runner Caster Semenya as she cruised to an easy win in her first-round heat of the 800 meters. But on Saturday evening, when Semenya will contest the 800-meter final, she’ll have the world’s eyes on her. “There is no more certain gold medal in the Rio Olympics than Semenya,” wrote Ross Tucker, an exercise scientist in South Africa, on his blog, The Science of Sport. “She could trip and fall, anywhere in the first lap, lose 20m, and still win the race.” If she does indeed dominate, some sports fans will be cheering Semenya, while others will be less inclined to celebrate, believing that she has an unfair advantage over her rivals. Semenya made headlines in 2009 amid rumors that track’s governing body, the International Association of Athletics Federations, had required her to undergo tests to confirm that she was female. Media accounts have reported that she has hyperandrogenism, a condition that causes higher-than-average testosterone levels — an allegation that neither Semenya nor the IAAF has publicly confirmed. Semenya’s case is the latest saga in sport’s checkered history of sex testing, a task that is purportedly aimed at creating an even playing field but — as I’ve discussed previously — raises serious questions about how athletics organizations treat women. Her muscular build, deep voice and remarkable results had raised suspicions among some of Semenya’s rivals about whether she was really a woman. “Just look at her,” said Mariya Savinova, a Russian runner now tangled in her country’s doping scandal.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 22601 - Posted: 08.25.2016

by Helen Thompson Some guys really know how to kill a moment. Among Mediterranean fish called ocellated wrasse (Symphodus ocellatus), single males sneak up on mating pairs in their nest and release a flood of sperm in an effort to fertilize some of the female’s eggs. But female fish may safeguard against such skullduggery through their ovarian fluid, gooey film that covers fish eggs. Suzanne Alonzo, a biologist at Yale University, and her colleagues exposed sperm from both types of males to ovarian fluid from female ocellated wrasse in the lab. Nesting males release speedier sperm in lower numbers (about a million per spawn), while sneaking males release a lot of slower sperm (about four million per spawn). Experiments showed that ovarian fluid enhanced sperm velocity and motility and favored speed over volume. Thus, the fluid gives a female’s chosen mate an edge in the race to the egg, the researchers report August 16 in Nature Communications. While methods to thwart unwanted sperm are common in species that fertilize within the body, evidence from Chinook salmon previously hinted that external fertilizers don’t have that luxury. However, these new results suggest otherwise: Some female fish retain a level of control over who fathers their offspring even after laying their eggs. Male ocellated wrasse come in three varieties: sneaky males (shown) that surprise mating pairs with sperm but don’t help raise offspring; nesting males that build algae nests and court females; and satellite males, which protect nests from sneakers but staying out of parenting. |© Society for Science & the Public 2000 - 2016

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 22563 - Posted: 08.17.2016

Carl Zimmer An eye is for seeing, a nose is for smelling. Many aspects of the human body have obvious purposes. But some defy easy explanation. For biologists, few phenomena are as mysterious as the female orgasm. While orgasms have an important role in a woman’s intimate relationships, the evolutionary roots of the experience — a combination of muscle contractions, hormone release, and intense pleasure — have been difficult to uncover. For decades, researchers have put forward theories, but none are widely accepted. Now two evolutionary biologists have joined the fray, offering a new way of thinking about the female orgasm based on a reconstruction of its ancient history. On Monday, in The Journal of Experimental Zoology, the authors conclude that the response originated in mammals more than 150 million years ago as a way to release eggs to be fertilized after sex. Until now, few scientists have investigated the biology of distantly related animals for clues to the mystery. “For orgasms, we kept it reserved for humans and primates,” said Mihaela Pavlicev, an evolutionary biologist at University of Cincinnati College of Medicine and an author of the new paper. “We didn’t look to other species to dig deeper and look for the origin.” The male orgasm has never caused much of a stir among evolutionary biologists. The pleasure is precisely linked to ejaculation, the most important step in passing on a male’s genes to the next generation. That pleasure encourages men to deliver more sperm, which is evolutionarily advantageous. For women, the evolutionary path is harder to figure out. The muscle contractions that occur during an orgasm are not essential for a woman to become pregnant. And while most men can experience an orgasm during sex, it’s less reliable for women. © 2016 The New York Times Company

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 22501 - Posted: 08.02.2016

Nicola Davis Female orgasm has perplexed scientists, fuelled an equality movement and propelled Meg Ryan to fame. Now researchers say they might have found its evolutionary roots. The purpose of the euphoric sensation has long puzzled scientists as it is not necessary for conception, and is often not experienced by women during sex itself. But scientists in the US have come up with an answer. Human female orgasm, they say, might be a spin-off from our evolutionary past, when the hormonal surges that accompany it were crucial for reproduction. “It is important to stress that it didn’t look like the human female orgasm looks like now,” said Mihaela Pavličev, co-author of the study from Cincinnati children’s hospital. “We think that [the hormonal surge] is the core that was maybe modified further in humans.” Writing in the journal JEZ-Molecular and Developmental Evolution, Pavličev and co-author Günter Wagner from Yale University describe how they delved into the anatomy and behaviour of a host of placental mammals to uncover the evolutionary origin of female orgasm, based on the hormonal surges associated with it. In mammals such as cats and rabbits, these surges occur during sex and play a crucial role in signalling for eggs to be released from the female’s ovaries. By contrast in a variety of other mammals, including humans and other primates, females ovulate spontaneously. © 2016 Guardian News and Media Limited

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 22498 - Posted: 08.01.2016