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Promiscuous females may be the key to a species' survival, according to new research by the Universities of Exeter and Liverpool. Published today (25 February) in Current Biology, the study could solve the mystery of why females of most species have multiple mates, despite this being more risky for the individual.

"Males and females differ in their biobehavioural response to stress, where males exhibit a heightened sympathetic response to stress compared with females. Specifically, Taylor et al. 1 propose that the classic "fight-or-flight" response to stress is adaptive for males, whilst females engage in a so-called "tend-and-befriend" response to stress. We propose that the Y-chromosome gene, SRY (sex-determining region on the Y chromosome), provides a genetic basis for the heightened sympathetic reactivity to stress and thus predominance of "fight-flight" response in males. Our idea is based on studies that demonstrate (i) the presence of SRY in brain regions and peripheral tissues abundant in catecholamines, (ii) the regulation of catecholamine synthesis and breakdown by SRY, and (iii) the role of SRY in voluntary movement and blood pressure in males"

A new strain of mosquitoes in which females cannot fly may help curb the transmission of dengue fever, according to UC Irvine and British scientists. Great idea or frankensketter?

In what may feel like a flashback to the porn wars of the '60s, a new study investigates the link between a country's relative gender equality and the degree of female "empowerment" in the X-rated entertainment it consumes. Researchers at the University of Hawaii focused on three countries in particular: Norway, the United States and Japan, which are respectively ranked 1st, 15th and (yikes) 54th on the United Nations' Gender Empowerment Measure (GEM). To simplify their analysis, their library of smut was limited to explicit photographs of women "from mainstream pornographic magazines and Internet websites, as well as from the portfolios of the most popular porn stars from each nation." Then they set out to evaluate each image on both a disempowerment and an empowerment scale, using respective measures like whether the woman is "bound and dominated" by "leashes, collars, gags, or handcuffs" or "whether she has a natural looking body." Their hypothesis was that societies with greater gender equity will consume pornography that has more representations of "empowered women" and less of "disempowered women." It turned out the former was true, but, contradictory as it may sound, the latter was not. "While Norwegian pornography offers a wider variety of body types -- conforming less to a societal ideal that is disempowering to the average woman -- there are still many images that do not promote a healthy respect for women," the researchers explain. In other words, Norwegian porn showed more signs of female empowerment, but X-rated images in all three countries equally depicted women in demeaning positions and scenarios. This, the researchers surmise, "suggests that empowerment and disempowerment within pornography are potentially different constructs." So, gender equality is accompanied by sexual interest in a broader range of beauty types but not a decrease in porn's infantilization of females, use of dominating fetish gear on women or any of the other characteristics th

"Males have more pronounced personalities than females across a range of species - from humans to house sparrows - according to new research. Consistent personality traits, such as aggression and daring, are also more important to females when looking for a mate than they are to males. Research from the University of Exeter draws together a range of studies to reveal the role that sexual selection plays in this disparity between males and females."

ScienceDaily (Jan. 20, 2011) - In birds as in people, female fertility declines with age. But some female birds can slow the ticking of their biological clocks by choosing the right mates, says a new study.

In a recent study, researchers show that a gene called DMRT1 found only on the Z chromosome partly explains bird "maleness". When a ZZ embryo gets less DMRT1, the embryos start to take on some female traits. These studies show us that bird gender can be partly explained by genetics. Not having enough of a single gene can keep a bird from becoming a bona fide male bird. But this doesn't rule out the possibility of a female gene being on the W chromosome. Scientists just haven't yet found one.

The more economically dependent a man is on his female partner, the more likely he is to cheat on her, according to new research.

When a cycad is ready to reproduce, it grows a large colorful cone, rich with pollen or seed. It signals its readiness by radiating heat or sending out attractive odors to pollinators, who travel back and forth. Once fertilized, the seed-rich cone is ripped apart by hungry seed carriers (who've included over the years, not just birds and insects, but dinosaurs, pterosaurs, bats; these trees have been eaten by just about everybody). But what if you can't find a mate? The tree in London (and its clones that are now growing in botanical gardens all over the world) is a male. It can make pollen. But it can't make the seeds. That requires a female. Researchers have wandered the Ngoya forest and other woods of Africa, looking for an E. woodii that could pair with the one in London. They haven't found a single other specimen. They're still searching. Unless a female exists somewhere, E. woodii will never mate with one of its own. It can be cloned. It can have the occasional fling with a closely related species. Hybrid cycads are sold at plant stores, but those plants aren't the real deal. The tree that sits in London can't produce a true offspring. It sits there, the last in its long line, waiting for a companion that may no longer exist.

ScienceDaily (June 27, 2011) - While the U.S. Food and Drug Administration notes "some concern" with the controversial chemical BPA, and many other countries, such as Japan and Canada, have considered BPA product bans, disagreement exists amongst scientists in this field on the effects of BPA in animals and humans. The latest research from the University of Missouri shows that BPA causes male deer mice to become demasculinized and behave more like females in their spatial navigational abilities, leading scientists to conclude that exposure to BPA during human development could be damaging to behavioral and cognitive traits that are unique to each sex and important in reproduction.

"There is a strong contemporary association between high heels and female sexuality. We investigated the hypothesis that one motivation for women wearing high heels is that it artificially increases the femininity of gait. Biomechanical analyses revealed that wearing high heels led to increased femininity of gait including reduced stride length and increased rotation and tilt of the hips. This groundbreaking study was published this month in the scientific journal Evolution and Human Behavior. It was written by Paul H. Morris, Jenny White, Edward R. Morrison and Kayleigh Fisher"

"This Disgraceful video was published by the European Commission for a campaign designed to attract more women to a career in science. The commission said that the video had to "speak their language to get their attention" and that it was intended to be "fun, catchy" and strike a chord with young people. "I would encourage everyone to have a look at the wider campaign and the many videos already online of female researchers talking about their jobs and lives," The original video was taken down after it received so many negative comments. "

"Previous research on rhesus macaques discovered that social rank influenced components of the stress response, brain, and immune system. With gene chip technology for measuring the expression of over 6,000 different genes, Tung, Gilad and colleagues at Yerkes, Emory University, and Johns Hopkins looked for the first time in primates at the effects of social rank on genetic function. Comparing 49 different female monkeys of different rank revealed significant changes in the expression of 987 genes, including 112 genes associated with immune system function. The result fits with data in monkeys where low rank and chronic stress lead to compromised immune function, and, more loosely, with human studies linking low socioeconomic status and high social stress to elevated disease risk."

"Social interactions require fast and efficient person perception, which is best achieved through the process of categorization. However, this process can produce pernicious outcomes, particularly in the case of stigma. This study used fMRI to investigate the neural correlates involved in forming both explicit ("Do you like or dislike this person?") and implicit ("Is this a male or female?") judgments of people possessing well-established stigmatized conditions (obesity, facial piercings, transsexuality, and unattractiveness), as well as normal controls. Participants also made post-scan disgust ratings on all the faces that they viewed during imaging. These ratings were subsequently examined (modeled linearly) in a parametric analysis. Regions of interest that emerged include areas previously demonstrated to respond to aversive and disgust-inducing material (amygdala and insula), as well as regions strongly associated with inhibition and control (anterior cingulate and lateral prefrontal cortex). Further, greater differences in activation were observed in the implicit condition for both the amygdala and prefrontal cortical regions in response to the most negatively perceived faces. Specifically, as subcortical responses (e.g., amygdala) increased, cortical responses (e.g., lateral PFC and anterior cingulate) also increased, indicating the possibility of inhibitory processing. These findings help elucidate the neural underpinnings of stigma"

What he and his orangutan buddies do in the forests of Sumatra tells scientists that advance trip planning and social networking aren't just human traits, A new study of 15 wild male orangutans finds that they routinely plot out their next day treks and share their plans in long calls, so females can come by or track them, and competitive males can steer clear.

"Evolution likes to keep what works best. The rest falls by the wayside. In theory, this means that the most "fit" variations, say, a color that looks poisonous or one particularly attractive to the ladies, would become the most common. By this logic, the many colors of the guppy should have conformed to a single common pattern long ago. But they haven't. Instead, the male guppies continue to show not only bright colors but also a high diversity of colors. What keeps the variety going? The rare-male effect. Female guppies prefer the males that are rare, no matter what their color pattern actually is. This effect has been documented in the laboratory in guppies and in other species like fruit flies."

"Dr Susan Hayes' facial approximation of the female Homo floresiensis"

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Scientists have developed the worlds male alternative to the female contraceptive pill.

(PhysOrg.com) -- The fact that our female ancestors dispersed more than our male ancestors can lead to conflicts within the brain that influence our social behaviour, new research reveals.

ScienceDaily (May 27, 2011) - Ionizing radiation is not without danger to human populations. Indeed, exposure to nuclear radiation leads to an increase in male births relative to female births, according to a new study by Hagen Scherb and Kristina Voigt from the Helmholtz Zentrum München.