Who doesn’t love a good duck penis? Carl Zimmer has written about them for The New York Times and The Loom. Ed Yong has written about them. So have I. In fact, duck penises are what won me a signed copy of The Immortal Life of Henrietta Lacks signed by Rebecca Skloot at Science Online 2010. So I feel like I owe them something in exchange. That’s why I donated money to research that will be measuring the explosive erection of the duck. And you can too.

As part of the #SciFund Challenge, a crowdfunding initiative for science research, ecologist Patty Brennan and biomechanics expert Diane Kelly are seeking funding for “Force of Duck: Measuring Explosive Erection.” There are three days left for the #SciFund Challenge, so go make their holidays a little brighter and help fund this fascinating research!

I’m excited to announce that my Friday Weird Science guest post for Neurotic Physiology was chosen for publication in The Open Lab 2011! For those unfamiliar with The Open Lab series, it is an annual anthology of the best writing on science blogs.

A note from Sci: The authors took the opportunity in the manuscript to thank their hardworking, and probably long suffering, medical illustrator. Yes, Matthew Timberlake, our hats are off. How we do thank YOU. You are, in your own way, a Real Man of Genius (TM)

Men, let’s talk about that space between your testicles and your anus (taint anus, taint balls – Sci). The length of your member doesn’t really have a whole lot to do with your reproductive fitness, but the length of your taint does. It’s time to put away the rulers and whip out the digital calipers!

A new study came out in PLoS ONE earlier this week, claiming to be the first assessment of anogenital distance in adult men, as well as the first examination of the relationship between anogenital distance and a man’s fertility. I hate to break it to the researchers from Baylor College of Medicine and Stanford University School of Medicine, but you are not the first. A VERY similar study came out two months ago in Environmental Health Perspectives, which Sci so awesomely blogged. As Sci mentioned, anogenital distance is used to sex animals– shorter for females, longer for males. Anogenital distance has also been studied in human infants, mirroring what we know to be true in the animal world (which makes sense, because we are animals)…but no one had studied this in adults up until recently, which leads us back to the sudden interest in measuring men’s taints.

Eisenberg ML, Hsieh MH, Walters RC, Krasnow R, Lipshultz LI, 2011 The Relationship between Anogenital Distance, Fatherhood, and Fertility in Adult Men. PLoS ONE 6(5): e18973.

Why do we care how long a man’s taint is, anyway? Well, because in the past half century there has been a reported decline in semen quality and male births with an increased rate in male genital abnormalities and testicular cancer….and no one likes cancer, or malformed genitals, or weak semen. Previous studies have shown that in addition to reduced anogenital distance, rodents exposed to certain phthalates (these are special chemicals added to plastics to increase flexibility and durability – Sci) had altered testicular size and Sertoli cell function, cells which nurture the developing sperm cells. Not only that, rodents exposed to endocrine disruptors during critical gestational windows for genital development saw irreparable alterations to penis length, anogenital distance, and testicular weight.

As I mentioned earlier, this study was fairly similar to the study that Sci blogged–the methodology was slightly different, and since there was some question regarding methodology in the comments on that post, I figure we’d go into the methodology a bit here. In this study, eligible patients were recruited from a urology clinic specializing in reproductive medicine. Patients evaluated for infertility that were over the age of 18 were eligible for the study, and a fertile control group was put together with a group of men that had a prior history of paternity. In order to measure their genitals, the men had to get into a frog-legged position. Oh yes, there are pictures:

(Note to self: Do not read papers on anogenital distance and male fertility while sitting in a busy airport such as Logan. You will unknowingly stumble upon said diagram while surrounded by people.)

How does one get ready for measurement anyway? Well first you lay on your back, and then touch the soles of your feet together, making sure to keep your feet 12 to 18 inches away from your butt. Oh, and you may want to get a Brazilian wax first. Someone is going to have to get all up in your business, and I’m sure they’d appreciate a clean work surface. Once ready for measuring, someone will take a pair of digital calipers to you, and measure from the back of the balls to the anus, which these researchers thought to be a more comfortable, reliable and reproducible measurement than measuring from the base of the penis (Though they don’t say what it’s MORE reliable than…A ruler? Bending over and spreading? – Sci). Penis length was taken as well, and testicular volume was estimated by one examiner (lucky man) who had the room at a balmy 78 to 80 degrees Farenheit, because…well….we all know what happens to the boys when its cold out.

(I use this photo every time I possibly get the chance-Sci)

All patients also had two semen analyses performed, and semen analyses were performed manually within an hour of collection. I’m going to assume that the semen samples were also OBTAINED manually, and not with a hands-free, semen-collecting robot (though they are becoming more popular! Coming soon to an artificial insemination clinic near you! – Sci).

The volume, density (millions of little swimmers per milliliter), and motility were recorded and multiplied to determine the total motile sperm count. Hormone assays were also processed for testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) (all of these are hormones which influence fertility in both men and women- Sci). Finally, statistical analyses were performed, including adjustments for age, race, FSH and BMI.

Most of the men in the study were white males (64%), but even when the the results were broken down by race, the length o’ taint differences between fathers and infertile men remained stable, with infertile, childless men having a significantly shorter anogenital distance when compared to fathers. Infertile men also had shorter stretched penis lengths and total testicular volumes than fertile men. All genital measurements seem to be correlated to each other, but those in the know can’t stress enough: CORRELATION DOES NOT EQUAL CAUSATION. Semen volume was similar in both fertile and infertile men, but the sperm density, motility and total mobile sperm count were significantly lower for infertile men. In both the unadjusted and adjusted models, anogenital distance and testicular volume were significantly correlated with total motile sperm count and sperm density, and sperm destiny and total motile sperm count increased with an increase in anogenital distance. For every 1 cm increase in taint, add another 4.3 million little swimmers per milliliter and the total motile sperm count increases by 6 million. There wasn’t any significant correlation seen between penis length and sperm count, which goes back to my opening statement — PUT AWAY YOUR RULERS! Women will not judge your marriage and fatherhood potential on the length of your penis…instead, they will base it upon your intelligence, your wit, your dashing good looks….and the length of your taint.

Eisenberg, M., Hsieh, M., Walters, R., Krasnow, R., & Lipshultz, L. (2011). The Relationship between Anogenital Distance, Fatherhood, and Fertility in Adult Men PLoS ONE, 6 (5) DOI: 10.1371/journal.pone.0018973

Just who exactly benefits from copulatory plugs, anyway?  Mating plugs have been documented in a broad range of animal groups, including insects, arachnids, reptiles and rodents and range from a gelatinous substance in bees and nematodes, to a more solid, coagulated protein mixture in primates, or even the whole appendage breaking off in the vagina.  These plugs all act like a cork in a wine bottle, keeping the contents inside- in this case, sperm- and prevent the female from being able to mate with any other suitors.  The one thing that binds all the various compositions of copulatory plugs is the belief that copulatory plugs are exclusively beneficial to the male.

A new study on nematode worms by researchers at the University of Teubingen, Germany is shaking that assumption, indicating that copulatory plugs may be beneficial for the female as well.  The study, published in the journal Frontiers in Zoology, found that in the nematode worm Caenorhabditis remanei, the plug acts as a form of ‘gift’ as opposed to preventing the females from mating again as previously thought.  And what female doesn’t like a gift after sex?

The copulatory plug probably evolved under sperm competition conditions, as a way to limit males’ competition with one another- blocking their competitor’s sperm and ensuring their fertilization of the egg, allowing them to pass on their genetic material.  The plug may not be as effective at this function, as the presence of a mating plug did not hinder how many times the female mated, or how attractive she was to males. However, it did have a positive effect on egg production and number of offspring, with plugged females producing an average of 29 percent more eggs and offspring than their unplugged counterparts in the study.  Nadine Timmermeyer, lead author of the study, said, “We found that plugging has a significant positive effect on egg production, suggesting that plugs may represent a beneficial act of a male towards its female partner rather than a competitive act between males.”

Discussing possible ways that such a seal may benefit both males and females, Timmermeyer said, “A plug may act as a seal, keeping sperm inside the female and preventing the entry of harmful pathogens. It may also contain substances that stimulate the female, or that have nutritious or antimicrobial properties.”  These worms have one thing right- if you’re going to have sex, shouldn’t it be beneficial for both?

Timmermeyer, N., Gerlach, T., Guempel, C., Knoche, J., Pfann, J., Schliessmann, D., & Michiels, N. (2010). The function of copulatory plugs in Caenorhabditis remanei: hints for female benefits Frontiers in Zoology, 7 (1) DOI: 10.1186/1742-9994-7-28

Yellow Mongooses mating, image c/o Wikimedia Commons

It’s sex week on The Loom. Carl Zimmer has a stack of papers on the evolution of sex that need blogging, so he will be covering the topic all week long.  Now, if you haven’t read any of  his stuff on sex, you may want to begin by delving into the world of kinky duck sex.  I owe Carl a special thank you for his Science Online 2010 discussion on duck genitalia, for it not, I may not have been the fasted tweeter in the South to respond to a trivia question regarding the shape of a duck’s penis, and thereby would never have won a copy of The Immortal Life of Henrietta Lacks by Rebecca Skloot (which, by the way, is a FANTASTIC read!)

Green Porno is back for a third season, and once again, it’s blue!  This time around, Isabella Rossellini adds to her sexual repertoire by teaming up with marine biologist Dr. Claudio Campagna to address sustainability.  Stripping shrimp, squid sex, and anchovy orgies are all served up this season.  And be sure not to miss the elephant seal birth!

Today has been quite a day!  We started off by heading out to Zee Best for breakfast, a French-owned cafe in Simpson Bay.  It truly does have zee best breakfast! (Sorry, couldn’t resist, hehe).  We then meandered to Marigot, the capital of the French side, to visit the market on the waterfront.  I bought a necklace and matching earrings made out of dried banana leaves, of all things!  Talk about creative uses of natural resources!!!

We then decided to do a little beach hopping.  I’m not sure which beach was really the “event” for the day.  It could be Le Galion, a family-friendly, protected beach.  I managed to snorkel a little because the water was so calm, but there wasn’t much to see.  There were TONS of windsurfers and kiteboarders, which was AWESOME to watch, in addition to a really cool, big, seagrass-covered sandbar where you could watch the incoming waves from the bay die out.  And for my geology fans, yes, they had beachrock.  If you are looking for a party, this is the place.  the locals set up generators with great music as they have their own private BBQs, but it definitely gets your feet moving.

As for the other “event” of the day…We went to Baie Orientale, the island’s most popular beach.  The further south you go, the less and less beachwear you will see, as the southernmost point of the beach is home to a nudist resort.  Yet even on the north end, BOY did I get an eyeful!  You see, we had just parked the car.  There was a man driving the wrong way on the one-way parking lot road, smiling and looking at me.  He had on no pants.  I figured okay weird, he is driving in a speedo.  Nope, no speedo either.  And one hand was on his ahem, gearshift.  NOT what you are expecting from a day at the beach.  Maybe it’s some cultural difference for which I missed the memo….WARNING!