Chapter 12. Sex: Evolutionary, Hormonal, and Neural Bases

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by Ariana Eunjung Cha Women having trouble getting pregnant sometimes try yoga, meditation or mindfulness, and some research suggests that psychological stress may affect infertility. But what about men: Does their mental state affect a couple's ability to conceive? The latest research on this subject was published Thursday in the journal Fertility and Sterility and suggests that a link between mental health and fertility may exist for women and men. The study involved data from 1,650 women and 1,608 men who were recruited through the National Institutes of Health's Reproductive Medicine Network at six sites in the United States. Most of the participants were couples, and they were undergoing some kind of fertility treatment, such as ovarian stimulation medication or artificial insemination, but not in vitro fertilization. Based on a questionnaire, about 6 percent of the women and 2 percent of the men were rated as having major depression. While the number of men with major depression in the analysis was small — just 34 — an analysis found differences between them and the other men in the study. Those with major depression were 60 percent less likely to have a live birth than men who did not have major depression. More specifically, of the 34, only three of the couples, or less than 9 percent, achieved a live birth. That compares with nearly 25 percent having a live birth for couples in which the male partner did not have major depression. © 1996-2018 The Washington Post

Keyword: Depression; Sexual Behavior
Link ID: 24987 - Posted: 05.17.2018

By Jeremy Rehm A man may be attractive because of his curly, blond hair or slick pin-striped suit, but strip everything away and one luring—maybe evolutionary—piece remains, a new study finds: how proportional his body is, especially his legs. Women prefer a man with legs that are about half his height, according to previous research; scientists believe that is an evolutionary result of women wanting to choose only healthy men. Legs that are too short, for example, have been linked to type 2 diabetes. But other proportions, such as arm length to body height or whether the elbow and knee divide a limb in half, can also relate to a person’s health. Do they influence women’s views as well? To answer this, researchers collected average body proportions from roughly 9000 men in the U.S. military and used them to create computer-generated images of male models (pictured). The scientists made the model’s arms and legs slightly longer or shorter, and then asked more than 800 heterosexual U.S. women to rank each model’s attractiveness. © 2018 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Evolution
Link ID: 24986 - Posted: 05.17.2018

Jesara Sinclair · Amanda Spidel, now pregnant with her third child, experienced postpartum depression with her first two. (Jesara Sinclair/CBC) Amanda Spidel had trouble getting pregnant with her first child. After her son was finally born, the stress of conceiving turned into anxiety around his health. Before long, her anxiety turned into postpartum depression, a condition that affects about 14 per cent of mothers. She struggled with her emotions and how she thought she should feel about motherhood. "I only wanted to be nothing but grateful, but he was very colicky, he cried all the time, and there were moments where it was really hard," she said. "All I could think was I should just be happy. Why am I not happy? But it was because he was crying all the time." Spidel's family doctor asked her how she was feeling at every visit, and that's how she reached out for help. "One day I went in and he asked that question and I just broke down and said, 'You know what — I'm not okay.'" Now 32 and expecting her third child, Spidel is speaking out about her experience with postpartum depression for the first time in hopes that it will help other mothers struggling not feel so alone. "It was really hard to admit that there was something wrong with me and it needed to be fixed," she said. "It's an illness, it really is and I was sick." ©2018 CBC/Radio-Canada.

Keyword: Depression; Hormones & Behavior
Link ID: 24970 - Posted: 05.13.2018

By Alexandra Sacks, M.D. A new mother finally gets her fussy baby to sleep and steps into a relaxing hot shower — with her glasses on. At a family barbecue she can’t recall the name of a relative she rarely sees. It’s easy to laugh off such lapses as “mommy brain,” but there remains a cultural belief that pregnancy and child care impact a woman’s cognition and mental life, long after a baby is born. Women have often chalked up these changes to hormones, fatigue and the intoxicating love for a new baby. Hormones do affect cognition, and, as anyone who has ever done shift work or had jet lag knows, sleep deprivation saps our mental abilities. And the current evidence in scientific literature suggests that pregnancy changes the brain on a physical, cellular level in ways that we are only beginning to understand. However, there is no convincing scientific evidence that pregnancy causes an overall decline in cognitive performance or memory. Instead, most experts believe that pregnant women’s brain changes are an example of neuroplasticity, the process in which the brain changes throughout life by reorganizing connections in response to the stimulation of new experiences, and neurogenesis, the process of growth that allows for new learning. A 2016 study in Nature Neuroscience found that even two years after pregnancy, women had gray matter brain changes in regions involved in social cognition or the ability to empathically understand what is going on in the mind of another person, to put yourself in their shoes. It may be that some subtle aspects of memory are sacrificed to enhance other areas of cognition. A 2010 study in Psychoneuroendocrinology showed that pregnant women experienced some impairment in the ability to remember words, but did not show changes in other memory functions such as recognition or working memory. This means that these women might forget the name of a character in their favorite TV show, for example, but would have no trouble in the type of memory that involves learning, reasoning and comprehension. © 2018 The New York Times Company

Keyword: Sexual Behavior; Learning & Memory
Link ID: 24969 - Posted: 05.12.2018

/ By David Dobbs If you think of beauty as something absolute — if you think Beyoncé or George Clooney is just beautiful, simple as that — Michael J. Ryan is here to tell you you’re wrong. Beauty, he asserts in this lovely and learned new book, exists only as a value-laden, capricious, and sometimes fleeting perception generated by the brain. Sexual selection is a counterintuitive theory that tries to explain bizarre forms and behavior. Even Darwin couldn’t quite wrap his mind around it. Beauty is literally in the eye of the beholder: It reveals itself only where and when the beholder thinks it does. In effect, then, to perceive beauty is to create it. And virtually all sexual species have evolved both the neural systems to perceive beauty and the traits that are or become so perceived. If you’re thinking this sounds circular and suspiciously chicken-and-egg, I’m here to tell you you’re right. Sexual selection is a complex, counterintuitive, three-pronged theory that seeks to explain both everyday sexual attraction and some of nature’s most bizarre forms, phenomena, and behavior. Even Darwin, who conceived the theory a century and a half ago, couldn’t quite wrap his mind around it, and the mature version that Ryan explores here is much and savagely disputed. The difficulty of explaining how sexual selection creates beauty is only Ryan’s first challenge. His second is that at least two notable books have already explained it memorably. The first, of course, was “The Descent of Man, and Selection in Relation to Sex” (Darwin’s “second most famous book,” notes Ryan), which explained it memorably but incompletely. Copyright 2018 Undark

Keyword: Emotions; Evolution
Link ID: 24966 - Posted: 05.12.2018

Laurel Hamers Toastier nest temperatures, rather than sex chromosomes, turn baby turtles female. Now, a genetic explanation for how temperature determines turtles’ sex is emerging: Scientists have identified a temperature-responsive gene that sets turtle embryos on a path to being either male or female. When researchers dialed down that gene early in development, turtle embryos incubating at the cooler climes that would normally yield males turned out female instead, researchers report in the May 11 Science. Scientists have struggled since the 1960s to explain how a temperature cue can flip the sex switch for turtles and other reptiles (SN Online: 1/8/18). That’s partly because gene-manipulating techniques that are well-established in mice don’t work in reptiles, says study coauthor Blanche Capel, a developmental biologist at Duke University School of Medicine. Previous studies showed certain genes, including one called Kdm6b, behaving differently in developing male and female turtles. But until recently, nobody had been able to tweak those genes to directly test which ones controlled sex. “This is the first venture down that path,” says Clare Holleley, an evolutionary geneticist at the Australian National Wildlife Collection in Canberra who wasn’t part of the study. “It's really quite a breakthrough.” In the new study, Capel’s lab collaborated with a group of Chinese researchers led by Chutian Ge of Zhejiang Wanli University in Ningbo. Ge’s team recently developed a way to lessen the activity of particular reptilian genes by injecting viruses bearing snippets of artificial RNA into developing eggs. |© Society for Science & the Public 2000 - 2018

Keyword: Sexual Behavior; Epigenetics
Link ID: 24963 - Posted: 05.11.2018

By Nicholas Bakalar Some earlier observational studies have suggested that children who are exclusively breast-fed have higher I.Q.s through adolescence, and even higher incomes at age 30. But a randomized trial, a more rigorous type of study that better controls for socioeconomic and family variables, found that breast-feeding in infancy had no discernible effect on cognitive function by the time children reached age 16. Researchers studied 13,557 children in Belarus, assigning them as newborns either to a program that promoted exclusive and prolonged breast-feeding or to usual care. Mothers and children were followed with six pediatrician visits during the first year of life to assess breast-feeding habits. The study is in PLOS Medicine. At age 16, the children took tests measuring verbal and nonverbal memory, word recognition, executive function, visual-spatial orientation, information processing speed and fine motor skills. There was no difference in scores between the two groups, except that breast-feeders had slightly higher scores in verbal function. “If you want to breast-feed in hope of increasing cognitive functioning scores, you may find some benefits in the early years,” said the lead author, Seungmi Yang, an assistant professor of epidemiology at McGill University in Montreal. “But the effect is going to be reduced substantially at adolescence. Other factors, such as birth order and parental education, are more influential.” © 2018 The New York Times Company

Keyword: Development of the Brain; Intelligence
Link ID: 24955 - Posted: 05.10.2018

Helen Thompson In the pitch-black waters beneath the Arctic ice, bowhead whales get funky. A small population of endangered bowheads belt an unusually varied repertoire of songs, which grows more diverse during mating season. Hunted to near extinction in the 1600s, these fire truck–sized mammals now number in the 300s in the frigid waters around the Svalbard archipelago in Norway. Underwater audio recorders captured the whales singing 184 acoustically distinct songs from October to April in 2010 through 2014. On the bowhead charts, a song's popularity is fleeting. Most recorded songs were heard for less than 100 hours total, although one song registered over 730 hours total. Some songs appeared in more than one month, but none repeated annually. December and January, likely the height of breeding season, saw a wider array of new bowhead songs than other months, researchers report in the April Biology Letters. Hearing a more distinct mixtape may play a role in enticing a female to mate. A hot cetacean band The Spitzbergen bowhead whale songbook contains a wide variety of tunes, and some stick around on the charts longer than others. Here each bubble corresponds to one of the 184 songs recorded by researchers from 2010 to 2014. The size of the bubble corresponds to the number of hours it was sung. Click on any of the dark green bubbles to hear that whale’s song. Groups of humpback whales don't change their tunes much in a given year, compared with bowheads. Only a few songbird species boast similar diversity. © Society for Science & the Public 2000 - 2018.

Keyword: Animal Communication; Sexual Behavior
Link ID: 24927 - Posted: 05.01.2018

/ By Cathleen O'Grady Growing up in Saudi Arabia, Aciel Eshky didn’t get the memo that science was for boys. When she was around 10 years old, her aunt started to teach her basic computer programming. From there, going on to a degree in computer science seemed like a natural fit. So when a classmate in her master’s program abroad told her that women were weaker than men at math, it came as a shock. “I was really annoyed,” Eshky says. “I felt like I was being bullied.” “If that means that you get fewer women in certain subjects, and more women in other subjects like psychology, it’s not necessarily a catastrophe.” Despite its dismal reputation for gender equality, Saudi Arabia has a surprising level of female graduates in the so-called STEM fields (science, technology, engineering, and mathematics). Ranked among the bottom 20 countries in the World Economic Forum’s Global Gender Gap Index in 2015, women nonetheless made up 39 percent of graduates in a cluster of “core” STEM subjects. This number is higher than Iceland’s 35 percent, even though the Nordic country ranks number one for gender equality. Norway, which has the second-highest level of gender equity, sees only 26 percent of women graduating with STEM degrees. Taken together with these numbers, Eshky’s experience is illustrative of the so-called “gender-equality paradox” reported in a recent headline-grabbing paper: Countries ranking higher on measures of gender equality, the study found, tend to have fewer women pursuing a STEM education than those further down the gender equality ranks. Copyright 2018 Undark

Keyword: Sexual Behavior
Link ID: 24910 - Posted: 04.27.2018

By Jim Daley Male fruit flies enjoy ejaculating, according to research published yesterday (April 20) in Current Biology. The study also found that when fruit flies are denied sex, they consume more alcohol than usual. It is the first study to demonstrate that insects find sex pleasurable. “We wanted to know which part of the mating process entails the rewarding value for flies,” says Galit Shohat-Ophir, a neurobiologist at Bar-Ilan University in Israel, in a statement. “The actions that males perform during courtship? A female’s pheromones? The last step of mating which is sperm and seminal fluid release?” To test if the latter is pleasurable, Shohat-Ophi and her colleagues used genetically engineered male fruit flies whose neurons controlling ejaculation can be activated by red light. These flies spent more time near the red light, presumably because they found ejaculation pleasurable, the authors say in the statement. David Anderson, a neurobiologist at Caltech who was not part of the study, tells National Geographic that it’s possible the pleasure the flies experienced wasn’t from ejaculation, but other reward systems in the brain that the stimulated neurons act upon. Next, the researchers plied the flies with alcoholic and nonalcoholic drinks and observed their response. The flies that had ejaculated preferred nonalcoholic drinks, while those that had not been exposed to the red light chose the alcoholic ones. “Male flies that are sexually deprived have increased motivation to consume alcohol as an alternative reward,” says Shohat-Ophi in the statement. © 1986-2018 The Scientist

Keyword: Sexual Behavior
Link ID: 24890 - Posted: 04.21.2018

/ By Joshua Brockman In May of last year, Dr. Chad Brummett spent part of a weekend in an Ann Arbor high school parking lot ensuring that the no-questions-asked drug take-back program he co-directs — called the Michigan Opioid Prescribing Engagement Network (Michigan OPEN) — went off without a hitch. The program is designed to give consumers in the area a convenient place to drop off unused or excess medications — ostensibly so they don’t end up being dumped or flushed into the environment, or land in the streets as part of the nation’s unchecked opioid epidemic. “We believe these programs may be an effective part of an all-of-the-above strategy.” Among the people stopping by that day, Brummett recalled: his own local pharmacist. “I thought that was really an eye-opening moment when I had my pharmacist attend the event to dispose of his pills,” said Brummett, who is also an associate professor of anesthesiology and the director of the Division of Pain Research at the University of Michigan. “I mean the irony is pretty deep, right?” According to a new analysis from the Government Accountability Office (GAO), some 4 million Americans reported misusing prescriptions in the prior month, and deaths related to opioid abuse are skyrocketing. Most people, the GAO suggests, get these drugs from friends or relatives, so providing a safe and convenient way for consumers to return unused medications, the thinking goes, could help. Currently, there are three approaches to disposing of unused prescription drugs that are sanctioned by the Drug Enforcement Administration. These include special disposal bins installed at pharmacies or other registered entities, mail-back programs, and take-back events like Brummett’s. Copyright 2018 Undark

Keyword: Depression; Hormones & Behavior
Link ID: 24872 - Posted: 04.17.2018

Jason Bittel In most North American hummingbirds, males court females by diving at them head on — but Costa’s hummingbirds (Calypte costae) perform their courtship dives off to the side. Researchers now find that this strategy allows the males to aim sounds at potential mates as if they were using a megaphone. During high-speed courtship dives, males fan their tails at the last second to create a high-pitched chirp. The faster the dive, the more those tail feathers vibrate and the higher the pitch created by the would-be Romeos. Researchers suspect that females prefer higher-pitched dives, which results in various strategies to boost the frequency of the noise a male makes. A study1 published on 12 April in Current Biology finds that male Costa’s hummingbirds can twist half of their tail feathers in the direction of the female, manipulating the volume and pitch of their chirps (see video). The researchers suspect that the targeted noise also masks audio cues that the females can use to judge how fast the males are diving. “You can think of the feather as being like a flashlight,” says Chris Clark, an ornithologist at the University of California, Riverside. “If you point the flashlight straight at something, the light is much brighter. And if you look at it from the side, at a 90-degree angle, there’s still some light but not nearly as much.” © 2018 Macmillan Publishers Limited

Keyword: Sexual Behavior; Evolution
Link ID: 24866 - Posted: 04.14.2018

By Lydia Denworth The demands of parenthood are so considerable that it’s fair to wonder why any adult takes on the challenge. Mammalian babies are especially helpless—and among mammals, only humans can see beyond individual sacrifice to understand a species’s survival depends on caring for its young. Yet there is remarkable consistency in the way all mammals change their behavior upon becoming parents. Suddenly they are motivated to care for their young, and know how to feed and shelter, nurture and protect new babies. Parents also give up a lot of adult social interaction, whether it is mating with other mice or going barhopping with friends. “What this means is that there is this instinctive or genetically programmed aspect to the drive to take care of offspring,” says neuroscientist Catherine Dulac of Harvard University. But if a complicated and variable behavior like parenting is hardwired, how would that work? Reporting in Nature this week, Dulac, also a Howard Hughes Medical Institute investigator, and her colleagues have provided a wiring diagram of the brain-wide circuit that coordinates parenting behavior in mice. The study marks the first deconstruction of the architecture of a brain circuit underlying a complex social behavior. The circuit they describe resembles the hub-and-spoke flight-routing system used by airlines and relies on a type of neuron that expresses the signaling molecule galanin. A relatively small number of these galanin neurons form a parenting command center—the medial preoptic area (MPOA)—in the hypothalamus, a brain structure responsible for controlling everything from appetite to sex drive. Responding to sensory input received from all over the brain, the neurons at the hub send distinct messages to at least 20 downstream subsets of galanin neurons. Like an airport terminal serving passengers according to their destinations, these subsets of cells, which the researchers dub “pools,” handle different facets of parenting behavior such as motor control of grooming or the motivation to parent at all. © 2018 Scientific American

Keyword: Sexual Behavior
Link ID: 24859 - Posted: 04.12.2018

Agence France-Presse How do bowhead whales in the unbroken darkness of the Arctic’s polar winter keep busy during breeding season? They sing, of course. From late autumn to early spring, off the east coast of Greenland, some 200 bowheads, hunted to the edge of extinction, serenade each other with compositions from a vast repertoire of song, according to a study published on Wednesday. “It was astonishing,” said the lead author, Kate Stafford, an oceanographer at the University of Washington’s Applied Physics Laboratory in Seattle, who eavesdropped on these subaquatic concerts. “Bowhead whales were singing loudly, from November until April” – non-stop, 24/7 – “and they were singing many, many different songs.” Stafford and three colleagues counted 184 distinct melodies over a three-year period, which may make bowheads one of the most prolific composers in the animal kingdom. “The diversity and inter-annual variability in songs of bowhead whales in this study are rivalled only by a few species of songbirds,” the study found. Unlike mating calls, songs are complex musical phrases that are not genetically hard-wired but must be learned. Only a handful of mammals – some bats and a family of apes called gibbons, for example – vocalise in ways akin to bird song, and when they do it is quite repetitive. The only other whale that produces elaborate songs is the humpback, which has been extensively studied in its breeding grounds near Hawaii and off the coast of Mexico. The humpback’s melody is shared among a given population over a period of a year, and gives way to a new tune each spring. Bowhead whales, it turns out, are far more versatile and would appear to improvise new songs all the time. © 2018 Guardian News and Media Limited

Keyword: Animal Communication; Language
Link ID: 24819 - Posted: 04.04.2018

By RANDI HUTTER EPSTEIN Getting a high testosterone reading offers bragging rights for some men of a certain age — and may explain in part the lure of testosterone supplements. But once you are within a normal range, does your level of testosterone, the male hormone touted to build energy, libido and confidence, really tell you that much? Probably not, experts say. Normal testosterone levels in men range from about 300 to 1,000 nanograms per deciliter of blood. Going from one number within the normal zone to another one may not pack much of a punch. “You don’t see the big improvement once men are within the normal range,” said Dr. Shalender Bhasin, an endocrinologist and professor of medicine at Harvard Medical School. The largest differences in terms of energy and sex drive are when men go from below-normal to normal levels. A 2015 study in JAMA found that sex drive improved among men who went from about 230, considered low, to 500, around the middle of what’s considered normal. There was no difference among men who moved within the normal range from 300 to 500. Testosterone does influence muscle size. The more testosterone a man takes, the larger the muscle — regardless of starting level, one reason the hormone is popular with young bodybuilders. But testosterone supplements do not seem to help frail older men walk farther or get out of chairs more easily, goals that doctors typically look for in aiding older patients. Beginning at age 30, testosterone levels drop, on average, about 1 percent a year. About 5 percent of men between the ages of 50 and 59 have low levels of testosterone along with symptoms like loss of libido and sluggishness, according to a few small studies. © 2018 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 24792 - Posted: 03.28.2018

By Abby Olena Some mouse mothers groom, lick, and nurse their babies more than others. In a study published in Science today (March 23), researchers demonstrate that this natural variation in maternal behavior is linked to the structure of pups’ genomes, specifically, the activation of one of the most common jumping genes in the genome, LINE-1. “What’s fascinating about the paper is the connection between experience, epigenetics, and restructuring of the genome,” says Moshe Szyf, a geneticist at McGill University in Montreal who did not participate in the work. “We usually think about epigenetics changes that don’t change the sequence, but here there was a connection of the maternal care, the change in methylation . . . and then restructuring.” Coauthor Tracy Bedrosian, who did the work as a postdoc at the Salk Institute and is now a scientist at Ohio-based Neurotechnology Innovations Translator, and her colleagues did not set out to study maternal behavior. Instead, they wanted to explore the effects of maternal stress and environmental enrichment on the retrotransposon LINE-1 (L1), which can copy and paste itself into new locations in the genome, in pups. To manipulate stress levels, they isolated and confined pregnant mice to a small area for a couple hours each day, and for enrichment, mice lived in groups in a large enclosure with toys and running wheels. Bedrosian says that they saw wild variations in L1 copy number between different litters of mice that didn’t seem to relate to their experimental manipulations. Perhaps, they reasoned, maternal behavior was involved. © 1986-2018 The Scientist

Keyword: Epigenetics; Sexual Behavior
Link ID: 24784 - Posted: 03.26.2018

By Jim Daley Mice exposed to bisphenol A (BPA) during pregnancy give birth to offspring with atypical brain development and abnormal behavior later in life, according to a study presented yesterday (March 19) at the annual meeting of the Endocrine Society in Chicago. Previous studies have linked BPA, which is found in a wide array of consumer products including plastic water bottles, to numerous diseases. In 2015, Deborah Kurrasch, a neuroscientist at the University of Calgary, and her colleagues found that the chemical can also alter brain development and cause hyperactivity at low doses in zebrafish. Kurrasch and her colleagues then decided to investigate whether similar alterations occurred in mammals, Dinu Nesan, a postdoctoral fellow in Kurrasch’s lab, said during a presentation. After feeding pregnant mice meals containing varying doses of BPA, the researchers observed that even when animals were exposed to low levels of the chemical—10 or 20 times below the recommended daily intake for humans—their offspring displayed significantly accelerated early neuron development. BPA exposure increased the number, size, and the rate of proliferation of neurons in the pups’ brains, but also reduced the “stemness,” or self-renewal capability, of cells, pushing them toward a more differentiated state. According to Nesan, the team also discovered that these effects could be “fully abrogated” with a combination of endocrine receptor and androgen receptor antagonists. © 1986-2018 The Scientist

Keyword: Development of the Brain; Neurotoxins
Link ID: 24773 - Posted: 03.21.2018

Amy Fleming Charles Ryan has a clinic in San Francisco at which he regularly relieves men of their testosterone. This “chemical castration”, as it is sometimes known, is not a punishment, but a common treatment for prostate cancer. Testosterone doesn’t cause the disease (currently the third most deadly cancer in the UK), but it fuels it, so oncologists use drugs to reduce the amount produced by the testicles. Ryan gets to know his patients well over the years, listening to their concerns and observing changes in them as their testosterone levels fall. Because it involves the so-called “male hormone”, the therapy poses existential challenges to many of those he treats. They know that every day, millions of people – from bodybuilders and cheating athletes to menopausal women – enhance their natural levels of testosterone with the aim of boosting their libido, muscle mass, confidence and energy. So what happens when production is suppressed? Might they lose their sex drive? Their strength? Their will to win? The fears are not always groundless. Side-effects can also include fatigue and weight gain. But Ryan has witnessed positives, too. As professor of medicine and urology at the University of California, he has noticed that the medical students who have passed through his clinic in the 18 years that he has been treating prostate cancer invariably comment: “Dr Ryan, your patients are so nice.” He replies, jokingly: “It’s because they don’t have any testosterone. They can’t be mean.” © 2018 Guardian News and Media Limited

Keyword: Aggression; Hormones & Behavior
Link ID: 24768 - Posted: 03.20.2018

By Anna Azvolinsky Researchers have tried to dissect the effects of an older father on kids’ longevity. One study found that kids with older dads had longer telomeres, which may indicate better health and longer lifespan, while another observed that kids with older dads have an increased risk of psychiatric disorders. So far, there have been very few experimental studies in animals that directly test whether paternal age has an affect on offspring telomere length and lifespan. Now, a team of researchers shows that bird embryos sired from old zebra finch fathers have shorter telomeres compared to those with the same moms and younger fathers. The study, published today (March 14) in Proceedings of the Royal Society B, is among the first to address whether paternal age affects telomere length of offspring using an experimental approach. “The experimental design of this study looking at the effect of paternal age on telomere length of [zebra finch] embryos is particularly strong, allowing for confidence in these results,” writes Dan Eisenberg, an anthropologist at the University of Washington who studies the effects of paternal age on telomere length in humans and chimpanzees, in an email to The Scientist. Jose Noguera, now at the University of Vigo, along with colleagues at the University of Glasgow, bred 32 middle-aged, female zebra finches first with both 16 four-month-old males and later with 16 four-year-old male birds. The team harvested the eggs, 139 in total, artificially incubated them for several days, then analyzed the telomere lengths of the embryos. © 1986-2018 The Scientist

Keyword: Development of the Brain; Sexual Behavior
Link ID: 24760 - Posted: 03.16.2018

By Hiroko Tabuchi If a sparrow sings his heart out on an oil field, but his would-be sweetheart can’t hear him above the oil pumps, what’s a bird to do? In Alberta, Canada, researchers analyzed hundreds of hours of Savannah sparrow love songs and discovered something extraordinary: To be heard above the din, the birds are changing their tune in complex ways that scientists are only starting to understand. “They’re tailoring their songs depending on which part of their message is the most affected,” said Miyako Warrington, a University of Manitoba biologist who led a recent study on how sparrows cope with noise from the oil and gas infrastructure that dots Canada’s landscape. “This seems to show a complex level of adaptation. It’s not just everybody talking louder.” Dr. Warrington is one of a growing number of scholars who study the noise generated by human activity — drills, turbines, roaring jet engines — and how that affects the natural world around us. Mining on the fringes of the Brazilian rain forest, for instance, is disrupting the calls of local black-fronted titi monkeys, a study found last year. Whales and dolphins are known to be particularly vulnerable to the groans of ship engines or offshore drilling, which can disrupt the complex ways they communicate. Research has shown that noise pollution has doubled the background sound levels in more than 60 percent of protected areas in the United States. And humans are not immune to the din. Epidemiologists have linked traffic noise to cardiovascular and other diseases. © 2018 The New York Times Company

Keyword: Animal Communication; Sexual Behavior
Link ID: 24758 - Posted: 03.15.2018