Chapter 8. Hormones and Sex

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Anil Oza Researchers have long known that areas of songbird brains that are responsible for singing grow during mating season and then shrink when the season is over. But one species, Gambel’s white-crowned sparrow (Zonotrichia leucophrys gambelii), does this on a scale that scientists are struggling to understand. A part of the male sparrow’s brain called the HVC grows from around 100,000 neurons to about 170,000 — nearly doubling in size — during the bird’s mating season. Although how the bird pulls off this feat is still a mystery, scientists who presented data at the annual Society for Neuroscience meeting in Washington DC on 11–15 November are closing in on answers. They hope their findings might one day point to ways of treating anomalies in the human brain. In most animals, when a brain region grows and shrinks, “frequently, it’s pretty detrimental on behaviour and function of the brain”, says Tracy Larson, a neuroscientist at the University of Virginia in Charlottesville who led the work. In particular, growth on this scale in mammals would cause inflammation and increase the pressure inside their skulls. But when it comes to the sparrows, “there’s something really fascinating about these birds that they can manage to do this and not have detrimental impacts”, Larson adds. Larson’s research has so far hinted that the sparrow’s brain is using a slew of tactics to quickly form and then kill a large number of neurons. One question that Larson wanted to answer is how the sparrow’s brain shrinks dramatically at the end of mating season. So she and her colleagues tagged cells in and around the HVCs of male sparrows with a molecule called bromodeoxyuridine (BrdU), which can become incorporated into the DNA of dividing cells. They also used hormone supplements to simulate breeding season in the birds. © 2023 Springer Nature Limited

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29029 - Posted: 12.02.2023

By Meeri Kim A woman’s menstrual cycle is driven by the ebb and flow of hormones that prepare the body for pregnancy. This symphony of hormones not only transforms the reproductive organs, but, according to recent research, also reshapes the brain. Live well every day with tips and guidance on food, fitness and mental health, delivered to your inbox every Thursday. Two studies released in October performed detailed brain scans of women at multiple points across the menstrual cycle, finding that the volume or thickness of certain regions change in sync with hormone levels. The areas of the brain highlighted by both studies are those in the limbic system, a group of brain structures that govern emotions, memory and behavior. “It’s like the brain being on a roller coaster every 28 days or so, depending on the length of the cycle,” said Erika Comasco, associate professor of women and children’s health at Uppsala University in Sweden, who was not involved in the research. “The importance of these studies is that they are building knowledge about the impact of these hormonal fluctuations on how the brain is structured.” “These brain changes may or may not alter the way we actually act, think and feel in our everyday lives. So the important next steps for the science are to put those pieces of the puzzle together,” said Adriene Beltz, associate professor of psychology at the University of Michigan, who was also not involved in the research. “Do the hormonal effects on brain structure influence how the brain works?” How hormones drive the menstrual cycle During a woman’s period, which marks the beginning of the menstrual cycle, hormones are at low levels. But they rise dramatically over a few weeks. Estrogen levels in the blood become eight times higher at ovulation around Day 14, while progesterone levels increase by 80-fold approximately seven days later. The production of follicle-stimulating hormone prompts the growth of an ovarian follicle into a mature egg, while a surge of luteinizing hormone triggers the release of the egg.

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29026 - Posted: 12.02.2023

Claudia López Lloreda The idea that the nervous system passes messages from one nerve cell to another only through synapses — the points where the cells link up end to end — is changing. Two studies show how messages can pass between cells over longer distances, through a ‘wireless’ nerve network in the worm Caenorhabditis elegans. Researchers had not appreciated the extent of this wireless communication, which happens when a molecule called a neuropeptide is released by one neuron and intercepted by another some distance away. The new studies, published in Nature1 and in Neuron2, map out the entire network of neuropeptide communication in a model organism for the first time. “We knew that these chemical connections existed, but this is probably the most comprehensive study in an entire nervous system,” says Gáspár Jékely, a neuroscientist at Heidelberg University in Germany who was not involved in the work. And what the research shows, he adds, is that “it’s not all about the synapses”. Researchers had previously worked out anatomical wiring maps — connectomes — showing how all the neurons in the fruit fly (Drosophila melanogaster) and in C. elegans are linked by their synapses. However, William Schafer, a neuroscientist at the MRC Laboratory of Molecular Biology in Cambridge, UK, wondered about the role of neuropeptides, which had been considered merely helpers in nervous-system messaging. “When I first started talking about this,” he says, “some people wondered, ‘is it all just kind of a soup’” where neuropeptides randomly float from one neuron to the next, “or can you really think about it like a network?” He and his colleagues analysed which neurons in the C. elegans nervous system expressed genes for certain neuropeptides and which ones expressed genes for the receptors of those neuropeptides. Using this data, the team predicted which pairs of nerve cells might be communicating wirelessly. On the basis of these results, the researchers generated a potential map of wireless connections in the worm, finding dense connectivity that looks very different from the anatomical wiring diagram of C. elegans. They published their findings in Neuron2 last week. © 2023 Springer Nature Limited

Keyword: Hormones & Behavior
Link ID: 29017 - Posted: 11.22.2023

By Annie Roth A few years ago, Nicolas Fasel, a biologist at the University of Lausanne in Switzerland, and his colleagues developed a fascination with the penises of serotine bats, a species found in woodlands and the attics of old buildings across Europe and Asia. Serotine bats sport abnormally long penises with wide, heart-shaped heads. When erect, the members are around seven times longer than the female’s vagina, and their bulbous heads are seven times wider than the female’s vaginal opening. “We wondered: How does that work? How can they use that for copulation?” Dr. Fasel recalled. What they discovered has overturned an assumption about mammalian reproduction, namely that procreation must always involve penetration. In a study, published Monday in the journal Current Biology, Dr. Fassel and his colleagues presented evidence that serotine bats mate without penetration, making them the first mammals known to do so. Instead of using their penises to penetrate their partners, the scientists found, the male bats use them to push their partner’s tail membrane out of the way so they can align their openings and engage in contact mating, a behavior similar to one found in birds and known as “cloacal kissing.” To learn how these bats overcome their substantial genital size difference, Dr. Fasel and his colleagues analyzed nearly 100 videos of serotine bats mating. The videos were provided by a bat rehabilitation center in Ukraine and a citizen scientist filming bats in the attic of a church in the Netherlands. The footage revealed a mating strategy unlike any other used by mammals. While the two bats hang upside down, the male climbs on the female’s back and grasps the nape of her neck. Once he has a firm hold, the male will use his erect penis to push the female’s tail membrane to the side and probe between her legs until he has located her vulva. The male then presses the heart-shaped head of his penis to the female’s vulva and holds it there until the deed is done. While this process took less than an hour for most of the couples the researchers observed, one pair went at it for nearly 13 hours. “It’s a really weird reproductive strategy, but bats are weird and have a lot of weird reproductive strategies,” said Patty Brennan, a biologist at Mount Holyoke College in Massachusetts who studies the evolution of genital morphology but was not involved in the study. © 2023 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 29014 - Posted: 11.22.2023

By Azeen Ghorayshi Doctors and patients have long known that antidepressants can cause sexual problems. No libido. Pleasureless orgasms. Numb genitals. Well over half of people taking the drugs report such side effects. Now, a small but vocal group of patients is speaking out about severe sexual problems that have endured even long after they stopped taking selective serotonin reuptake inhibitors, the most popular type of antidepressants. The drugs’ effects have been devastating, they said, leaving them unable to enjoy sex or sustain romantic relationships. “My clitoris feels like a knuckle,” said Emily Grey, a 27-year-old in Vancouver, British Columbia, who took one such drug, Celexa, for depression from age 17 to 23. “It’s not a normal thing to have to come to terms with.” The safety label on Prozac, one of the most widely prescribed S.S.R.I.s, warns that sexual problems may persist after the drug is discontinued. And health authorities in Europe and Canada recently acknowledged that the medications can lead to lasting sexual issues. But researchers are only just beginning to quantify how many people have these long-term problems, known as post-S.S.R.I. sexual dysfunction. And the chronic condition remains contested among some psychiatrists, who point out that depression itself can curb sexual desire. Clinical trials have not followed people after they stop the drugs to determine whether such sexual problems stem from the medications. “I think it’s depression recurring. Until proven otherwise, that’s what it is,” said Dr. Anita Clayton, the chief of psychiatry at the University of Virginia School of Medicine and a leader of an expert group that will meet in Spain next year to formally define the condition. Dr. Clayton published some of the earliest research showing that S.S.R.I.s come with widespread sexual side effects. © 2023 The New York Times Company

Keyword: Depression; Sexual Behavior
Link ID: 28996 - Posted: 11.11.2023

By Bruce Bower Female chimps living in an East African forest experience menopause and then survive years, even decades, after becoming biologically unable to reproduce. The apes are the first known examples of wild, nonhuman primates to go through the fertility-squelching hormonal changes and live well beyond their reproductive years. The finding raises new questions about how menopause evolved, UCLA evolutionary anthropologist Brian Wood and colleagues conclude in the Oct. 27 Science. Until now, females who experience menopause and keep living for years have been documented only in humans and five whale species. It’s unclear what evolutionary benefit exists to explain such longevity past the point of being able to give birth and pass on one’s genes. Although evolutionary explanations for menopause remain debatable, the new finding reflects an especially close genetic relationship between humans and chimps, Wood says. “Both [species] are more predisposed to post-reproductive survival than other great apes.” Some evidence suggests that female fertility ends at similar ages in humans and chimps (Pan troglodytes) if our ape relatives live long enough, says anthropologist Kristen Hawkes of the University of Utah in Salt Lake City. But in other studies, female chimps, such as those studied by Jane Goodall at Tanzania’s Gombe National Park starting in 1960, aged quickly and often died in their early 30s, usually while still having menstrual cycles, she says. “What’s surprising [in Wood’s study] is so many females living so long after menopause,” Hawkes says. © Society for Science & the Public 2000–2023.

Keyword: Hormones & Behavior; Evolution
Link ID: 28975 - Posted: 10.28.2023

By Liz Fuller-Wright, The latest exploration of music in the natural world is taking place in Mala Murthy ’s lab at the Princeton Neuroscience Institute, where Murthy and her research group have used neural imaging, optogenetics, motion capture, modeling and artificial intelligence to pinpoint precisely where and how a fruit fly’s brain toggles between its standard solo and its mating serenade. Their research appears in the current issue of the journal Nature. “For me it is very rewarding that, in a team of exceptional scientists coming from different backgrounds, we joined forces and methodologies to figure out the key characteristics of a neural circuit that can explain a complex behavior — the patterning of courtship song,” said Frederic Römschied, first author on this paper and a former postdoctoral fellow in Murthy’s lab. He is now a group leader at the European Neuroscience Institute in Göttingen, Germany. “It might be a surprise to discover that the fruit flies buzzing around your banana can sing, but it’s more than music, it’s communication,” said Murthy, the Karol and Marnie Marcin ’96 Professor and the director of the Princeton Neuroscience Institute. “It’s a conversation, with a back and forth. He sings, and she slows down, and she turns, and then he sings more. He’s constantly assessing her behavior to decide exactly how to sing. They’re exchanging information in this way. Unlike a songbird, belting out his song from his perch, he tunes everything into what she’s doing. It’s a dialogue.” It might be a surprise to discover that the fruit flies buzzing around your banana can sing, but it’s more than music, it’s communication. By studying how these tiny brains work, researchers hope to develop insights that will prove useful in the larger and more complex brains that are millions of times harder to study. In particular, Murthy’s team is trying to determine how the brain decides what behavior is appropriate in which context. © 2023 The Trustees of Princeton University

Keyword: Animal Communication; Sexual Behavior
Link ID: 28959 - Posted: 10.14.2023

Nicola Davis Science correspondent When it comes to avoiding unwanted male attention, researchers have found some frogs take drastic action: they appear to feign death. Researchers say the findings shed new light on the European common frog, suggesting females do not simply put up with the male scramble for mates – a situation in which several males can end up clinging to a female, sometimes fatally. “It was previously thought that females were unable to choose or defend themselves against this male coercion,” said Dr Carolin Dittrich, the first author of the study from the Natural History Museum of Berlin. But the research suggests this may not be the case. “Females in these dense breeding aggregations are not passive as previously thought,” Dittrich said. Writing in the journal Royal Society Open Science, Dittrich and her co-author, Dr Mark-Oliver Rödel, report how they placed each male frog in a box with two females: one large and one small. The mating behaviour was then recorded on video. The results, obtained from 54 females who experienced the clutches of a male, revealed that 83% of females gripped by a male tried rotating their body. Release calls such as grunts and squeaks were emitted by 48% of clasped females – all of whom also rotated their body. Tonic immobility – stiffening with arms and legs outstretched in a pose reminiscent of playing dead – occurred in 33% of all females clasped by a male, with the team adding it tended to occur alongside rotating and calling. Smaller females, they note, more frequently employed all three tactics together than larger ones. While unusual, tonic immobility – it turned out – had been seen before. “I found a book written in 1758 by Rösel von Rosenhoff describing this behaviour, which was never mentioned again,” Dittrich said. © 2023 Guardian News & Media Limited

Keyword: Sexual Behavior
Link ID: 28956 - Posted: 10.12.2023

By Sandra G. Boodman Bridget Houser felt despairing. In the months before her 2018 wedding, Houser, who had never struggled with her weight, noticed that it inexplicably began to creep up. In response she doubled the length of her runs to eight miles, took back-to-back high intensity workout classes and often consumed only water, coffee and fruit during the day before a spartan, mostly vegetable, dinner. Yet no matter what Houser did, her weight stubbornly increased and her oval face grew round, a transformation that was glaringly obvious in comparison with her identical twin sister. Houser wondered whether the five pounds she gained despite her herculean effort was a corollary of other problems. For the previous two years she had battled a string of maladies: first daily headaches, then crippling anxiety, followed by insomnia, hair loss and acne, something she’d never endured as a teenager. “Stress was the universal explanation,” recalled Houser, a controller for a small business in Chicago. When doctors suggested that her upcoming marriage might be a cause of her problems, Houser considered, then rejected, the theory. It just didn’t jibe with her feelings. In early 2019, about six months after her wedding, Houser insisted that her doctors perform several tests. They ultimately revealed that her symptoms weren’t the result of stress or marital misgivings but of a serious illness that had been smoldering for years. After successful treatment followed by a long recovery Houser, now 34, feels far better than she did during those miserable years in her late 20s. “I wish I’d been nicer to myself and not blamed myself for what was going on,” she said.

Keyword: Hormones & Behavior
Link ID: 28951 - Posted: 10.10.2023

Hannah Devlin Science correspondent Pregnancy leads to a permanent rewiring of neurons, according to research that gives new insights into the influence of hormones on behaviour. The research, in mice, revealed that their parenting instincts were triggered by changes in the brain that occur in response to oestrogen and progesterone late in pregnancy. Similar changes are likely to occur in the human brain, according to scientists, who said the work could pave the way for fresh understanding into parenting behaviour and postpartum mental health. Dr Jonny Kohl, who led the research at London’s Francis Crick Institute, said: “We know that the female body changes during pregnancy to prepare for bringing up young. One example is the production of milk, which starts long before giving birth. Our research shows that such preparations are taking place in the brain, too.” The findings are consistent with brain imaging research in women showing changes to brain volume and brain activity that endure long after pregnancy. Although Kohl pointed out that “parenting is obviously a lot more complex in humans”. “We have NCT classes, observational learning, all these environmental influences,” he added. “We don’t have to rely on those hormonal changes to such a degree.” a newborn baby boy is checked by nurses in a hospital maternity theatre Smoking in pregnancy increases risk of premature birth threefold, study finds Read more The studies were carried out in mice, which undergo a dramatic shift in behaviour, with virgin females showing no interest in pups, and mouse mothers spending most of their time looking after young. Previously it had been widely assumed that the onset of this behaviour occurred during or just after birth, possibly triggered by hormones such as oxytocin. However, the latest research puts the change at an earlier stage and also suggests that the changes may be permanent. © 2023 Guardian News & Media Limited

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28949 - Posted: 10.07.2023

By Carl Zimmer In more than 1,500 animal species, from crickets and sea urchins to bottlenose dolphins and bonobos, scientists have observed sexual encounters between members of the same sex. Some researchers have proposed that this behavior has existed since the dawn of the animal kingdom. But the authors of a new study of thousands of mammalian species paint a different picture, arguing that same-sex sexual behavior evolved when mammals started living in social groups. Although the behavior does not produce offspring to carry on the animals’ genes, it could offer other evolutionary advantages, such as smoothing over conflicts, the researchers proposed. “It may contribute to establishing and maintaining positive social relationships,” said José Gómez, an evolutionary biologist at the Experimental Station of Arid Zones in Almería, Spain, and an author of the new study. But Dr. Gómez cautioned that the study, published on Tuesday in the journal Nature Communications, could not shed much light on sexual orientation in humans. “The type of same-sex sexual behavior we have used in our analysis is so different from that observed in humans that our study is unable to provide an explanation for its expression today,” he said. Previous studies of same-sex sexual behavior have typically involved careful observations of a single species, or a small group of them. Dr. Gómez and his colleagues instead looked for the big evolutionary patterns that gave rise to the behavior in some species but not others. The researchers surveyed the 6,649 species of living mammals that arose from reptilelike ancestors starting roughly 250 million years ago. Looking over the scientific literature, they noted which of them had been seen carrying out same-sex sexual behaviors — defined as anything from courtships and mating to forming long-term bonds. The researchers ended up with a list of 261 species, or about 4 percent of all mammalian species, that exhibited these same-sex behaviors. Males and females were about equally likely to be observed carrying out same-sex sexual behavior, the analysis showed. In some species, only one sex did. But in still others — including cheetahs and white-tailed deer — both males and females engaged in same-sex sexual behavior. © 2023 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28943 - Posted: 10.05.2023

By Till Hein Human couples could learn a lot from seahorses. The marine marvels spend only quality time together. They flirt, swim together, and mate. The rest of time they go their own way, drifting in ocean currents, leisurely eating their fill. But they do look forward to getting together again. Right after sunrise, male and female seahorses approach one another, gently rubbing their noses together and then begin to circle each other. Many of them make seductive clicking noises. The partners gracefully rock back and forth, as though to the beat of underwater music. They dance and cuddle together dreamily, as though they’ve lost track of time. However, love can be dangerous for seahorses. During partner dancing, hormones are released that can make their camouflage fade. This causes changes in color, so their bodies begin to glow, and the contrasts in the patterns of their skin become more pronounced. Researchers hypothesize this is how seahorses signal their willingness to mate. The partner dances also serve as a means of seduction. Before mating, courtship can take many hours. Finally, the female signals that she’s ready. She swims up toward the water surface, pointing her snout toward the sky, and stretches her body out straight as a stick—a pose that is irresistible to the male. The stallion of the sea presses his chin against his chest and makes his prehensile tail open and close like a switchblade. This enables him to pump water into his brood pouch to show his beloved mare of the sea how roomy it is. Soon afterward, the mare and stallion of the sea snuggle up together closely and let themselves drift upward. They press their bodies together so that their snouts and abdomens are touching. On account of the curves in their body posture, the space between them looks like the shape of a heart. Then, something amazing takes place. A tubular rod appears in the middle of the female seahorse’s belly, which looks a little like a penis, the so-called ovipositor. At the climax of the love scene, both partners lift their heads as though in ecstasy, curving their backs, and the female seahorse transfers her eggs into the male’s brood pouch, while her partner fertilizes them with his sperm. © 2023 NautilusNext Inc., All rights reserved.

Keyword: Sexual Behavior; Evolution
Link ID: 28923 - Posted: 09.23.2023

Hannah Devlin Science correspondent The brain circuit that causes the sound of a newborn crying to trigger the release of breast milk in mothers has been uncovered by scientists. The study, in mice, gives fresh insights into sophisticated changes that occur in the brain during pregnancy and parenthood. It found that 30 seconds of continuous crying by mouse pups triggered the release of oxytocin, the brain chemical that controls the breast-milk release response in mothers. “Our findings uncover how a crying infant primes its mother’s brain to ready her body for nursing,” said Habon Issa, a graduate student at NYU Langone Health and co-author of the study. “Without such preparation, there can be a delay of several minutes between suckling and milk flow, potentially leading to a frustrated baby and stressed parent.” The study showed that once prompted, the surge of hormones continued for roughly five minutes before tapering off, enabling mouse mothers to feed their young until they were sated or began crying again. The observation that a mother’s breasts can leak milk when they hear a crying baby is not new. But the latest research is the first to identify the brain mechanisms behind what the scientists described as the “wail-to-milk pipeline”, and could pave the way for a better understanding of the challenges of breastfeeding for many women. The findings, published in Nature, showed that when a mouse pup starts crying, sound information travels to an area of its mother’s brain called the posterior intralaminar nucleus of the thalamus (PIL). This sensory hub then sends signals to oxytocin-releasing brain cells (neurons) in another region called the hypothalamus. Most of the time these hypothalamus neurons are “locked down” to prevent false alarms and wasted milk. However, after 30 seconds of continuous crying, signals from the PIL built up and overpowered the in-built inhibitory mechanism, setting off oxytocin release. © 2023 Guardian News & Media Limited

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28919 - Posted: 09.21.2023

By Sarah Lyall The author Cat Bohannon was a preteen in Atlanta in the 1980s when she saw the film “2001: A Space Odyssey” for the first time. As she took in its famous opening scene, in which a bunch of apes picks up a bunch of bones and quickly begins using them to hit each other, Bohannon was struck by the sheer maleness of the moment. “I thought, ‘Where are the females in this story?’” Bohannon said recently, imagining what those absent females might have been up to at that particular time. “It’s like, ‘Oh, sorry, I see you’re doing something really important with a rock. I’m just going to go over there behind that hill and quietly build the future of the species in my womb.” That realization was just one of what Bohannon, 44, calls “a constellation of moments” that led her to write her new book, “Eve: How the Female Body Drove 200 Million Years of Human Evolution.” A page-turning whistle-stop tour of mammalian development that begins in the Jurassic Era, “Eve” recasts the traditional story of evolutionary biology by placing women at its center. The idea is that by examining how women evolved differently from men, Bohannon argues, we can “provide the latest answers to women’s most basic questions about their bodies.” These include, she says: Why do women menstruate? Why do they live longer? And what is the point of menopause? These are timely questions. Thanks to regulations established in the 1970s, clinical trials in the United States have typically used mostly male subjects, from mice to humans. (This is known as “the male norm.”) Though that changed somewhat in 1994, when the National Institutes of Health updated its rules, even the new protocols are replete with loopholes. For example: “From 1996 to 2006, more than 79 percent of animal studies published in the scientific journal Pain included only male subjects,” she writes. © 2023 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28907 - Posted: 09.13.2023

Nicola Davis Science correspondent Whether it’s seeing Jesus in burnt toast, a goofy grin in the grooves of a cheese grater, or simply the man in the moon, humans have long perceived faces in unlikely places. Now researchers say the tendency may not be fixed in adults, suggesting it appears to be enhanced in women who have just given birth. The scientists suggest the finding could be down to postpartum women having higher levels of oxytocin, colloquially referred to as the “love” or “trust” hormone because of its role in social bonding. “These data, collected online, suggest that our sensitivity to face-like patterns is not fixed and may change throughout adulthood,” the team write. Writing in the journal Biology Letters, researchers from Australia’s University of Queensland and the University of the Sunshine Coast describe how they set out to investigate whether the propensity to see faces in inanimate objects – a phenomenon known as face pareidolia – changes during life. Previous research has suggested that when humans are given oxytocin, their ability to recognise certain emotions in faces increases. As a result, the team wanted to explore if the hormone could play a role in how sensitive individuals are towards seeing faces in inanimate objects. The researchers used an online platform to recruit women, with participants asked if they were pregnant or had just given birth – the latter being a period when oxytocin levels are generally increased. The women were each shown 320 images in a random order online and asked to rate on an 11-point scale how easily they could see a face. While 32 of the images were of human faces, 256 were of inanimate objects with patterns that could be said to resemble a face, and 32 depicted inanimate objects with no such facial patterns. The team gathered data from 84 pregnant women, 79 women who had given birth in the past year, and 216 women who did not report being pregnant or having recently had a baby. © 2023 Guardian News & Media Limited

Keyword: Sexual Behavior; Attention
Link ID: 28906 - Posted: 09.13.2023

By Veronique Greenwood Floating languorously through forests and jungles of the Americas, longwing butterflies have many secrets. The 30-odd species in this group include many mimics. The wing markings on some distantly related species of longwings are so similar they inspired one Victorian naturalist to theorize that harmless species could mimic deadly ones to avoid predators. In the age of genomic sequencing, biologists have found other oddities in longwings. In a paper published last week in the Proceedings of the National Academy of Sciences, researchers report that female zebra longwings can see colors that males cannot, thanks to a gene on their sex chromosome. Understanding how it got there might shed light on how differences between sexes can evolve. Like primates, butterflies have a handful of proteins that are sensitive to certain wavelengths of light that, working together, produce the ability to distinguish colors. Curious about the zebra longwing’s vision, Adriana Briscoe, a professor at the University of California, Irvine, and an author of the new paper, asked a student to check the species’ genome for a well-known color vision gene. The gene, known as UVRh1, codes for a protein that is sensitive to ultraviolet light. To her surprise, it was nowhere to be found. Digging deeper, and drawing on genomic data from additional zebra longwings, Dr. Briscoe and her colleagues discovered that UVRh1 was there, but only in females. With lab experiments, they confirmed that females could see markings males couldn’t. They eventually pinpointed the gene in an unexpected place: the butterfly’s tiny sex chromosome. Sex chromosomes in butterflies are unstable, often shedding genes that are picked up by other chromosomes, or lost entirely, Dr. Briscoe said. That makes them a somewhat unusual place to keep something as important as a gene for color vision. © 2023 The New York Times Company

Keyword: Sexual Behavior; Vision
Link ID: 28872 - Posted: 08.19.2023

By Pam Belluck The Food and Drug Administration on Friday approved the first pill for postpartum depression, a milestone considered likely to increase recognition and treatment of a debilitating condition that afflicts about a half-million women in the United States every year. Clinical trial data show the pill works quickly, beginning to ease depression in as little as three days, significantly faster than general antidepressants, which can take two weeks or longer to have an effect. That — along with the fact that it is taken for just two weeks, not for months — may encourage more patients to accept treatment, maternal mental health experts said. The most significant aspect of the approval may not be the features of the drug, but that it is explicitly designated for postpartum depression. Several doctors and other experts said that while there were other antidepressants that are effective in treating the condition, the availability of one specifically shown to address it could help reduce the stigma of postpartum depression by underscoring that it has biological underpinnings and is not something women should blame themselves for. The hope is that it will encourage more women to seek help and prompt more obstetricians and family doctors to screen for symptoms and suggest counseling or treatment. “This is a patient population that just so often falls through the cracks,” said Dr. Ruta Nunacs, a psychiatrist with the Center for Women’s Mental Health at Massachusetts General Hospital. “When women are told, ‘You have postpartum depression,’ it’s embarrassing, it is demeaning, it makes them feel like a bad mom.” She added, “There’s also a lot of stigma about taking antidepressant medication, so that might make this treatment more appealing because it’s really a treatment specific for postpartum depression.” © 2023 The New York Times Company

Keyword: Depression; Sexual Behavior
Link ID: 28867 - Posted: 08.05.2023

By Alejandra Manjarrez Rafael Jiménez Medina learned how to hunt elusive Iberian moles in the fields of southern Spain in the 1980s, when he was a young PhD student in genetics at the University of Granada. A local hunter of the moles (Talpa occidentalis) taught him how to capture these solitary, aggressive and territorial animals. The moles dig subterranean galleries and labyrinths in the meadows of the Iberian Peninsula, especially those with soft soils rich in earthworms, their favorite food. Such activity can benefit the soil — by aerating or mixing it — but the moles’ presence and constant movement in cultivated land raise the ire of farmers, who pay hunters to get rid of them. Jiménez Medina had a different motivation for hunting these subterranean mammals. His doctoral project was to visualize and analyze their chromosomes, which meant collecting, preparing and examining samples from the testes of males. His lab analyses led to a curious finding: Some of the moles he had identified as males were in fact genetically females — that is, their sex chromosomes were XX (female) and not XY (male). The confusion, we now know, stems from the unusual composition of the reproductive organs of female moles. In contrast to most female mammals, which have only ovaries, female Iberian moles also have testicular tissue. This tissue anatomically resembles male testicles but differs in that it produces testosterone but no sperm. The female mole’s organs are composed of both an ovarian and a testicular portion and are known as ovotestes. In addition, female moles have a clitoris covered with a foreskin and with an elongated appearance that resembles a penis; they urinate through this structure. Another unique anatomical feature is that during these females’ juvenile stage, the vaginal orifice remains closed. © 2023 Annual Reviews

Keyword: Sexual Behavior; Evolution
Link ID: 28849 - Posted: 07.19.2023

By Darren Incorvaia When Ambika Kamath was a graduate student in evolutionary biology at Harvard University, she knew one thing for sure: She wasn’t going to research anoles, the lizards that her adviser, Jonathan Losos, specialized in. “I started out as one of those rebellious renegades,” Kamath says, determined to pursue her own research subject. So she went to India for a couple of years to study the poorly understood fan-throated lizards. But when she tried to map out their territories, she found chaos. “All of the lizards were moving everywhere,” she says. Losos encouraged her to work with anoles after all, because it was well established that males hold individual territories that they protect from other males, and females only mate with the male whose territory they reside in. That would make it more straightforward for Kamath to study how anole territoriality differed across habitat types, like forests and parks. So Kamath went to Florida, where she identified individual anoles and tracked their movements day in, day out. Kamath studied the anoles “in a larger area, in a longer period of time than anyone else had ever done,” says Losos, who is now at Washington University in St. Louis. But instead of revealing territorial differences, this massive dataset showed that the anoles weren’t actually territorial in the first place. Kamath looked into the historical record to see where the idea of anole territoriality originated. It started with a 1933 paper that described frequent sexual behavior between male lizards in the lab. The authors had concluded that this lab behavior must be “prevented by something” in the wild, Kamath says, which they inferred was the males protecting territories. “The very first conclusion,” she says, “was based on a homophobic response to observing male-male copulation.” That shaky conclusion caught on, and later researchers assumed it to be true. Introducing a feminist perspective © Society for Science & the Public 2000–2023.

Keyword: Sexual Behavior; Attention
Link ID: 28842 - Posted: 07.06.2023

By Sujata Gupta Teenagers in the United States are in crisis. That news got hammered home earlier this year following the release of a nationally representative survey showing that over half of high school girls reported persistent feelings of “sadness or hopelessness” — common words used to screen for depression. Almost a third of teenage boys reported those same feelings. “No one is doing well,” says psychologist Kathleen Ethier. She heads the U.S. Centers for Disease Control and Prevention’s Division of Adolescent and School Health, which has overseen this biennial Youth Risk Behavior Survey since 1991. During the latest round of data collection, in fall 2021, over 17,000 students from 31 states responded to roughly 100 questions related to mental health, suicidal thoughts and behaviors, sexual behavior, substance use and experiences of violence. One chart in particular garnered considerable media attention. From 2011 to 2021, persistent sadness or hopelessness in boys went up 8 percentage points, from 21 to 29 percent. In girls, it rose a whopping 21 percentage points, from 36 to 57 percent. Some of that disparity may arise from the fact that girls in the United States face unique stressors, researchers say. Compared with boys, girls seem more prone to experiencing mental distress from social media use, are more likely to experience sexual violence and are dealing with a political climate that is often hostile to women’s rights (SN: 7/16/22 & 7/30/22, p. 6). But the gap between boys and girls might not be as wide as the numbers indicate. Depression manifests differently in boys and men than in girls and women, mounting evidence suggests. Girls are more likely to internalize feelings, while boys are more likely to externalize them. Rather than crying when feeling down, for instance, boys may act irritated or lash out. Or they may engage in risky, impulsive or even violent acts. Inward-directed terms like “sadness” and “hopelessness” miss those more typically male tendencies. And masculine norms that equate sadness with weakness may make males who are experiencing those emotions less willing to admit it, even on an anonymous survey. © Society for Science & the Public 2000–2023

Keyword: Depression; Development of the Brain
Link ID: 28841 - Posted: 07.01.2023