Tag: sex & reproduction

Studly Fish Aren't Born, They're Made—Sometimes Overnight

By Joseph Castro | July 18, 2011 4:16 pm

Some people like to say that men are always ready (and eager) for sex. Whether or not that’s true for humans, Stanford University researchers have recently learned that it is the case for certain male fish. Downtrodden male African cichlids, whose reproductive systems are so suppressed that biologists thought the fish couldn’t produce sperm, can successfully spawn within hours of rising to power, according to a new study published in the journal Proceedings of the Royal Society B.

Like many other animal species, a single leader—the biggest, baddest male—runs each group of African cichlids. This alpha male, which often sports vibrant blue scales, monopolizes the females and beats down other, weaker males in the community. (High school, anyone?) Because of this sexual exclusion, subordinate males suffer a noticeable pallor, decreased levels of reproductive hormones, and severely shrunken testes. Essentially, the fish trade sperm production for growth spurts, in hopes of someday overtaking the alpha male. Why waste energy making sperm if you can’t use it, right?

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The Better to Ignore You With: Female Frogs Deaf to Males' Ultrasonic Calls

By Joseph Castro | June 17, 2011 3:06 pm

The concave-eared torrent frog.

Wouldn’t it be nice if we could hear each other over the low-frequency roar of jetliners and subway trains? For some rodents, bats, and marine mammals, environmental noise doesn’t normally pose a problem, as they can communicate at ultrasonic frequencies (greater than 20 kHz, just above our maximum hearing range). There are also a couple of amphibians that exhibit this trait, but in an odd twist, researchers have now learned that female concave-eared torrent frogs are deaf to the ultrasonic components of the males’ calls.

The concave-eared frog is a tree-loving native of the Huangshan Mountains in China. In choosing this woodsy area, the nocturnal amphibians must put up with one minor annoyance: streams that produce constant ambient noise. In 2006, Jun-Xian Shen, a biophysicist at the Chinese Academy of Science in Beijing, and his research team discovered that the frogs get around this sonic clutter by adding ultrasonic frequencies to their normal calls (pdf). The frogs were the first non-mammalian vertebrate found to do this, and scientists have since learned that Borneo’s hole-in-the-head frogs (yes, that’s the actual name) also chirp in ultrasonic frequencies. After finding these ultrasonic noises, researchers wanted to know what they were saying with these super-high-pitched croaks.

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What the Duck? Lady Mallards May Get Down With Bright-Billed Drakes to Avoid STDs

By Patrick Morgan | April 13, 2011 3:57 pm

When it comes to mallard bills, brighter is better: A bright yellow bill is duck-speak for “I’m healthy,” attracting more female ducks than dingy green ones. After discovering that avian semen has antibacterial properties, scientists then found that the semen of brighter-billed males killed more bacteria than the semen of darker-billed ones. It implies that by seeking out bright-billed males, female ducks are protecting themselves against bacteria-related sexually transmitted diseases.

In her experiment, University of Oslo researcher Melissah Rowe collected semen from ducks (a feat unto itself—the videos in this link are amazing, but watch at your own risk) of various bill colors, and then tested how well the semen killed bacteria such as E. coli. She found that ducks whose bills had more carotenoids—an organic pigment that brightens bills—also had semen that more effectively killed E. coli. However, they discovered that the semen’s effectiveness against the bacteria S. aureus wasn’t associated with bill color, possibly implying that this bacteria doesn’t pose much harm to ducks.

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The Measure of a Man's Private Parts Is Connected to His Fertility

By Patrick Morgan | April 4, 2011 4:11 pm

When it comes to male fertility, length matters—the length between the scrotum and anus, that is. New research suggests that measuring a man’s “anogenital distance,” or AGD,  is a fast, low-tech, relatively accurate method of getting an idea of the quality of a man’s sperm.

In a new study, University of Rochester professor Shanna Swan and her colleagues broke out the measuring tape and assessed the anus-to-scrotum distance of 126 men born in 1988 or later. The men whose AGD’s were shorter than the average of two inches were 7.3 times more likely to have low sperm counts than their more well-endowed…er, well-distanced, brethren. These men with shorter AGD’s also had low sperm motility and poor sperm morphology.

So why on Earth, you’re wondering, would this be the case?

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The Genetic Gamesmanship of a Seven-Sexed Creature

By Patrick Morgan | March 4, 2011 9:40 am

What could be better than two types of sexes? For one organism, the answer isn’t three, but seven! And to top it off, these seven sexes aren’t evenly distributed in a population, although researchers have now developed a mathematical model that can accurately estimate the probabilities in this crap-shoot game of sexual determination.

Meet Tetrahymena thermophila, which in addition to its seven different sexes—conveniently named I, II, III, IV, V, VI, and VII—has such a complex sex life that it requires an extra nucleus. This fuzzy, single-celled critter has a larger macronucleus that takes care of most cellular functions and a smaller micronucleus dedicated to genetic conjugation.

The other odd thing about this one-celled wonder is that the population of the seven sexes are skewed, leading Unversity of Houston researcher Rebecca Zufall and her colleagues to ask: What gives?

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Devious Mating 101: The Lesson of the Fairy Wren and the Butcherbird

By Patrick Morgan | January 28, 2011 1:11 pm

You’d think birds would hush up at the sound of a predator, especially if that predator’s name is the “butcherbird.” But that’s not the style of the male splendid fairy-wren, and it turns out he has a good reason for raising a ruckus when the butcherbird calls: it helps him get a mate.

Researchers studied this wren-butcherbird interaction in Southern Australia by playing iPod bird songs for wild wrens to hear. As the press release reports, the researchers determined the the males were engaging in a form of “vocal hitchhiking”:

“We have shown that females do, in fact, become especially attentive after hearing butcherbird calls,” said Emma Greig, PhD, first author of the study and currently a postdoctoral researcher at Cornell University. “So, it seems that male fairy-wrens may be singing when they know they will have an attentive audience, and, based on the response of females, this strategy may actually work!”

But how do you tell if a bird is paying attention? The scientists calculated attention by whether the female wren looked towards the call and responded with her own song. Female wrens responded overwhelmingly when the researchers played the male wren’s distinctive “Type II” call immediately following the cry of a butcherbird. From the press release:

“The most exciting possibility is that Type II songs have a sexual function, and that females are more easily stimulated by, or receptive to, displays after being alerted by a predator, such that the male’s song is especially attractive,” Greig said.

Their study, published in the journal Behavioral Ecology, should spur research into other bird species–like the white-throated magpie jay and the fairy gerygone–whose males display a similar post-predator call. And birds may not be the only ones who use fear as an aphrodisiac–anyone headed to a horror movie for Friday date night?

Related Content:
80beats: How Male Antelopes Lie to Get More Sex: With False Alarm Calls
Not Exactly Rocket Science:The Bird That Cries Hawk: Fork-Tailed Drongos Rob Meerkats With False Alarms
DISCOVER: The Best Ways To Sell Sex
DISCOVER: The Mating Game’s Biggest Cheaters (photo gallery)

Image: flickr / dicktay2000


Sneezy After Sex? You Could Have Post Orgasmic Illness Syndrome

By Patrick Morgan | January 20, 2011 2:00 pm

If you experience feverish, burning-eyed orgasms, don’t rejoice–you should probably consider visiting your doctor. Scientists believe such flu-like symptoms arise when men are allergic to their own semen.

It’s called post orgasmic illness syndrome (POIS). Although the term has been around since 2002, researchers led by Marcel Waldinger, a professor of sexual psychopharmacology at Utrecht University in the Netherlands, have for the first time shown that some men suffer from a semen allergy. Such men, after ejaculating, not only have burning eyes and fever-like feelings that can last for a week, but also feel as tired as post-marathon runners and have noses that run faster than Usain Bolt.

In one study published in the Journal of Sexual Medicine this week, the researchers pricked the skin of 33 POIS-diagnosed men with their own diluted semen, and discovered that nearly 90 percent of them had allergic reactions as a result. As Reuters reports:

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Study Says: Laugh Your Way to a Pregnant Belly

By Patrick Morgan | January 14, 2011 12:39 pm

Whether you chortle, chuckle, or cackle, having a good laugh–as we’ve known for decades–reduces stress. And according to an Israeli study, it can also make you pregnant.

OK, that’s a slight exaggeration. But researchers who studied 219 women undergoing in vitro fertilization (IVF) discovered that women were more likely to become pregnant if they were paid a visit by a professional “medical clown” after the procedure. The numbers speak for themselves: 36 percent of the clowned women became pregnant, whereas only 20 percent of the un-clowned women conceived.

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Toasty Testicles From Laptops Could Make for Less Fertile Nerds

By Jennifer Welsh | November 8, 2010 11:25 am

laptop-balls-1Being a computer nerd just keeps getting worse. Not only can being addicted to the interwebz make it hard to meet chicks, but now research is showing that a man’s relationship with his laptop computer can affect even his most intimate of areas.

The study, titled “Protection from scrotal hyperthermia in laptop computer users,” studied how laptop positioning affected testicle temperature. Participants were asked to sit with a laptop on their knees while the research team monitored the temperature of their scrotum (both the left and right sides).

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CATEGORIZED UNDER: Sex & Mating, Technology Attacks!

Don’t Try This at Home: Flamingos Get Their Blush From Oily Rump Glands

By Jennifer Welsh | October 29, 2010 5:55 pm

flamingoResearchers found new evidence of the importance of make-up while studying Spanish flamenco dancers flamingos. The scientists discovered that the birds augment their signature coloring by applying tints drawn from their own glands–and they use their painted plumage to attract mates.

The hue of the leggy birds’ feathers come primarily from the pigments in their diet, but researcher Juan Amat found that they also secrete the colored pigments, called carotenoids, from their preen glands. Flamingos (and many other birds) press their heads to the preen glands at the base of their tails to pick up feather-protecting oils, which they then spread around their bodies.

The researchers realized that those oils contain pigments, ranging from red to yellow, by keeping an eye on the flamingos’ feathers and behavior: They noticed that the coloring of the birds was brightest during the mating season, and quickly diminished after they found a mate. Amat told BBC News:

“The rubbing is time-consuming,” Dr Amat told BBC News. “And the more frequently the birds practise it, the more coloured they appear. If the birds stop the rubbing, [their] plumage colour fades in a few days because carotenoids[pigments] bleach quickly in the sunlight.”

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