Friday Weird Sex Blogging

Mating slugs

clock — Wed, 06 May 2009 08:42:23 +0000

Mating slugs

I know PZ has recently posted a picture and a video of slugs mating. But these pictures were taken here in North Carolina, by blog reader Kris Barstow, who says:

The year was 1999 plus or minus a year, the site was a few miles from Asheboro, NC. I don't recall the season, but it was warm, and there is definitely a chill there in the cold seasons, so I assume spring or summer. It was about half an hour after sunrise; I was walking my dog. I would occasionally carry my camera "just because ..."

I saw these two acting strangely on the surface of the wooden shed. They actually attached themselves, then went into freefall. They twined around each other, and then a moist pouch was extruded below them. White froth was present but in moderation.

I don't recall what exactly happened after that. They remained suspended for some time, and the likeliest thing is that I left them to their passion.

So, can someone identify the species?

clock Wed, 05/06/2009 - 04:42

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A Picture Is Worth A Thousand Words

animal behavior

Friday Weird Sex Blogging

sex

How big are they? Limax maximus mates dangling from a mucous thread like that. Adults are about thumb sized.

I would have pegged them as Limax maximus because of that acrobatic behaviour. Haven't seen them that colour before so they may be something else. The ones I see in my garden here in southern Australia are usually more grey and black.

Friday Weird Sex Blogging - Postscript to Pittendrigh's Pet Project - Phototaxis, Photoperiodism and Precise Projectile Parabolas of Pilobolus on Pasture Poop

clock — Sat, 11 Apr 2009 01:29:43 +0000

Friday Weird Sex Blogging - Postscript to Pittendrigh's Pet Project - Phototaxis, Photoperiodism and Precise Projectile Parabolas of Pilobolus on Pasture Poop

We have recently covered interesting reproductive adaptations in mammals, birds, insects, flatworms, plants and protists. For the time being (until I lose inspiration) I'll try to leave cephalopod sex to the experts and the pretty flower sex to the chimp crew.

In the meantime, I want to cover another Kingdom - the mysterious world of Fungi. And what follows is not just a cute example of a wonderfully evolved reproductive strategy, and not just a way to couple together my two passions - clocks and sex - but also (at the very end), an opportunity to post some of my own hypotheses online.

The star of today's story is Pilobolus - not the dance troupe, but the fungus. Have you ever been out in the country visiting a farm? If so, have you seen piles of manure stashed somewhere or just lying around the paddocks? And if that manure was a little older and starting to dry out and decompose, you may have observed fine white fuzz on its surface. Have you seen that? That fuzz is Pilobolus, one of a number of species in the genus. If you had a strong magnifying glass with you, and you trained it a the fuzz, you would have seen something like this:

Pilobolus has a portion of its life-cycle in which it has to pass through the digestive tract of a large mammal. Since large mammals roam far and wide, this is a great way for the fungus to disperse. There is one problem, though: once excreted out with the feces, how do fungal spores get back into a large mammal?

Unlike rabbits, large mammals do not tend to eat their own manure. Actually, if you observe a field with a properly kept cow herd - a relatively small number of animals in a relatively large area, and rotated regularly between fields - you will notice that all the cows poop in one spot and no cow ever comes close to that spot to graze. So, what is a poor Pilobolus to do? It gets ready, it aims, and it shoots!

Ready

Pilobolus assumes the position, builds a weapon, fills it with ammunition, aims and shoots. The position is on top of the manure. The ammunition are spores, packaged tightly at the very tip of the filament. The weapon is the sporangiophore, a large swelled organ right below the tip. The sporangiophore fills up with sap - osmotically active compounds - which builds up pressure until it is about 7 kilograms per square centimeter (100 pounds per square inch). There is also a line of weakness where the cap - the spore package - joins the sporangiphore vesicle. In the end, the pressure causes the sporangiophore to explode which sends the package of spores far, far away - if the wind is in the right direction, as far as 12 feet.

The goo from the sporangiophore goes with the spore package. It is very sticky, so wherever the spores land, they tend to stay put. Ideally, that is on a blade of grass which is far enough from the manure pile to have a chance of getting eaten by a cow.

Here is a pretty picture of Pilobolus and a photomicrograph of the spore mass (crushed by the slide and slipcover):

[images from BioImages]

This is already cool (though wait for more coolness below), but this also has an economic and environmental impact. Pilobolus spores themselves do not cause harm to their mammalian hosts, but some parasitic worms have evolved a neat trick - hitchiking on the Pilobolus spores right into the digestive tracts of large mammals. While domestic cattle is regularly dewormed, the real problem is with wild large ruminants, especially in places in which they do not have large areas to roam in, as in the Yellowstone Park. Here is a photograph of a Pilobolus harboring the Dyctiocaulus larvae:

Aim

So, Pilobolus shoots its spores really far away, by exerting enormous pressure on the 'cap'. But, anyone who's been in an artillery unit in the military will tell you that the distance is determined by angle. Soldiers manning the cannons know that an approximately 45 degree angle of the cannon will result in the greatest distance for the projectile. But a cannon projectile is a large, heavy object (also smooth and aerodynamic), so air resistance plays almost no part in this calculation - the force of gravity is the only force that the projectile needs to overcome.

A fungal spore is a microscopic object. At the small scale (pdf), physics works a little differently - gravity effects are minimal and the air resistance (drag) is the main determinant of maximal distance. Thus, 45 degrees is not neccessarily the optimal angle for achieving the greatest distance.

Frances Trail and Iffa Gaffoor, working with Steven Vogel at Duke University, made some calculations (which I have not seen and I do not think they got published, but I heard them from Dr.Vogel), looking at the shape and size of spore-caps of several species of Pilobolus (they published data on some other shooting fungi, though - you can read the paper here). The optimal angle for maximal distance ranges, in different species, between 9 and 30 degrees, the most common fuzz found on cow dung requiring about 15 degrees. The maximal distance, without wind, is about 6-7 feet. Quite right. Six feet is about as close as cows will come to a cowpie in well managed cattle establishments.

But does Pilobolus really shoot at 15 degrees? Well, what it does is it shoots towards the Sun. The way Pilobolus aims is through positive phototaxis. Like a sunflower, it follows the Sun in the sky and shoots at the Sun in the morning.

If you place Pilobolus in a box with light coming in only through a pinhole, all the fungi will shoot their spores at the pinhole.

How does Pilobolus see the light? Beneath the sporangium is a lens-like subsporangial vesicle, with a light-sensitive `retina'. It controls the growth and shape of the sporangiophore quite precisely. Thus, the packet of spores is always aimed at a light source:

Shoot

So, the Pilobolus spores are found 6-12 feet away from the manure and they reproduce quite nicely even in the best managed cattle herds. So, they are probably shot at their optimal 15-degree angle. But they shoot at the Sun. Ergo, they shoot at the Sun when the Sun is about 15 degrees above the horizon.

One can think of two possible ways this can be achieved. One would be a mechanical sensor that triggers the explosion when the angle between the stalk and the cap is 15 degrees. This would work only if each individual was always standing upright on a flat surface, which is not the case on the rough relief of a manure pile.

The other strategy is to time the release so it coincides with the time when the Sun is about 15 degrees above the horizon. But, the trajectory of the Sun differs at different times of year.

In the middle of the summer in a high latitude, when the daylength is, let's say, 18 hours, the Sun shoots straight up from the East and reaches the zenith right above exactly at noon. Thus, the Sun is around 15 degrees above the horizon about 90 minutes after dawn.

In winter, when the day may be only 6 hours long, the Sun traverses the sky low above the horizon from East to South to West, and may reach 15 degrees much slower (some Earth scientist in the audience can make a quick calculation here), e.g., 2 or even 3 hours after dawn.

How does the Pilobolus adjust to seasonal differences in Sun's trajectory? By using its circadian clock, which entrains to different photoperiods with a systematically different phase:

Actually, the Pilobolus was the first fungus in which a clock was discovered. The effects of daylength on timing of spore-release was discovered back in 1948. The endogenous rhythmicity - meaning that the spores get shot every day even if there is no light present (in continous darkness) - was discovered in 1951. The major breakthrough was provided by Esther-Ruth Uebelmesser:

At the same time that Schmidle published his findings, Esther-Ruth Uebelmesser (1954) dedicated her thesis work to the same subject. Her thesis is remarkable in many ways. Many of her experiments anticipated circadian protocols, frequently used in later years (different T-cycles and photoperiods, reciprocity, night interruption experiments, entrainment by temperature cycles, etc.). Although she did not fully exploit the richness of her experimental approaches in her interpretations, she must be considered a pioneer of the field and has certainly inspired Colin Pittendrigh to use Pilobolus as a circadian model system (Bruce et al., 1960). Probably, Pittendrigh abandoned this model system because of the unbearable smell penetrating the laboratory when the bovine dung media was prepared (Michael Menaker and Gene Block, personal communication, December 2000).

---------------------------snip----------------------------

While in Neurospora accumulation of conidia (conidial bands) appears to be driven in these protocols with a constant phase angle in reference to lights-off (Fig. 2A), the phase angle of the spore-shooting rhythm in Pilobolus was systematically different with changing cycle lengths (Fig. 2B), possibly reflecting circadian entrainment. Closer investigation, however, revealed that the Pilobolus sporulation rhythm is also driven by the LD cycle, but unlike in Neurospora, by lights-on. Sporulation in Pilobolus is triggered by light, and the spores mature for approximately 28 h before they are shot (see arrows in Fig. 2B and C). The maturation time represents a kind of memory capacity for prior events. This is seen in experiments in which the fungi were released to DD (e.g., from LD 4:4 shown in Fig. 2C). The rhythm, synchronized to a given light cycle, persists for another 28 h until the endogenous circadian control takes over. Thus, depending on conditions, the production of asexual spores in Pilobolus is controlled both by the clock (phase angle) and by light (a driven spore release once per LD cycle).

[images from Roenneberg and Merrow 2001]

What this all means is that a circadian clock in this fungus is entrained by the dawn (not dusk) and it integrates photoperiodic information in a manner that is consistent with the need to shoot spores towards the Sun at the time of the morning when the Sun first reaches 15 degrees (actually, the tracking movement of the spore lags the Sun by about 20 minutes - fungi are slow to move - but even that is probably compensated for by the circadian clock).

Moreover, Pittendrigh's students discovered that the Pilobolus clock is extremely sensitive to light (both intensity and duration of light). Its clock requires only a millisecond of light to be completely reset.

This is where the story ends, for the time being. But there are still gaps.

For instance, I am not sure if it was ever tested in the laboratory that Pilobolus actually shoots at 15 degrees. This is, according to Dr.Vogel, relatively easy to do, by placing the fungi on a manure-based medium at the center of one of those transparent semi-spheres used by exhibitors at various product fairs (e.g., technology fairs). The ejected spores stick to the inside of the transparent plastic and can be seen from the outside. Measuring the length of the arc from the desk to the spore (and knowing the radius) is all one needs to calculate the angle.

Second, we still do not know for sure if the Pilobolus cues in to the season-specific photoperiod (more likely) or the season-specific Sun trajectory (less likely). One can, in the laboratory, dissociate these two factors by exposing groups of fungi to summer-specific photoperiod and winter-specific trajectory (using a strong flashlight attached to a string and mounted on an arc-shaped wire, attached to a little motor) or vice-versa, as well as season-specific photoperiod with diffuse (instead of focused) light source.

Finally, an evolutionary question. Horses are not as picky as cows concering the distance from the manure at which they will graze. Pilobolus lives in our horses and shows up in the manure all the time. Is there relaxed selection for the populaitons (species?) that live in horses? Is their timing off? Is their angle-determination lousy? This would be an easy head-to-head test in the lab (and field) as well.

References:

Bruce VC,Weight F, and Pittendrigh CS (1960) Resetting the sporulation rhythm in Pilobolus with short light flashes of high intensity. Science 131:728-730.

Till Roenneberg and Martha Merrow, Seasonality and Photoperiodism in Fungi, JOURNAL OF BIOLOGICAL RHYTHMS, Vol. 16 No. 4, August 2001 403-414

Uebelmesser E-R (1954) Ãber den endogenen Tagesrhythmus der Sporangienbildung von Pilobolus. Arch Mikrobiol 20:1-33.

clock Fri, 04/10/2009 - 21:29

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Friday Weird Sex Blogging - Sex On The (Dreaming) Brain

clock — Sat, 11 Apr 2009 01:25:41 +0000

Friday Weird Sex Blogging - Sex On The (Dreaming) Brain

(First posted on February 5, 2007) Last week I asked if you would be interested in my take on this paper, since it is in Serbian (and one commenter said Yes, so here it is - I am easy to persuade):

Stankovic Miodrag, Zdravkovic Jezdimir A., and Trajanovic Ljiljana,
Comparative analysis of sexual dreams of male and female students (PDF). Psihijatrija danas 2000, Vol. 32, No. 4, pp. 227-242

Here is the English-language Abstract:

The subject of research is analysis of connection between sexuality as instinctive function and dreams with sexual content as cognitive function. The sample consisted of 656 students, 245 males and 411 females. Research showed significant difference between genders concerning sexual dreams their appearance, frequency, image of sexual partner, and content subjective emotional experience during dreams and talk about sexual fantasies. Based on the obtained data, the authors believe that dreams with sexual content are not learned behavior, but biologically determined sexual behavior, and that cognitive elaboration of contents and objects of sexual fantasies is secondarily environmentally conditioned.

Reading this paper was quite an interesting experience. It's been a while since I last read a paper in Serbian so the language itself (with so many Serbianized English terms) appears strange - in my opinion English is for science, Serbian is for poetry!

The first thing that hit me was the very beginning of the Introduction. I have forgotten over the years how many papers there start with pointing out the deepest historical origins of their topic, usually starting with Ancient Greece (we used to joke back when I was still there in the 1980s that every paper there starts with the same phrase: "Even the ancient Greeks thought...."). The very first mentions are of the writings of Ovid, Galen and Aristotle and what they wrote about sexual dreams.

Next comes the obligatory smackdown of Freud establishing the hard-nosed, hard-science attitudes of the authors, followed by a brief review of the old theries on dreaming (a very short version of something like this), followed by a brief review of the classic in the field of sex research - the Kinsey review, focusing on what it has to say about erotic dreams coupled with orgasms/nocturnal emissions.

I have mixed feelings about this approach. On one hand, starting every paper with Ancient Greeks is silly. On the other hand, I wish more papers in English would spend a little bit of time at the very beginning providing the historical, philosophical and theoretical background and context instead of immediatelly jumping into last month's literature on the topic (at least press releases and blog posts about the papers should cover this ground).

The main argument of the Introduction, I think, is that the world has changed (emancipation of women, etc.) yet the erotic dreams in both sexes have not changed since the Kinsey report, indicating a biological basis for them (and for the sex differences in them) instead of cultural effects.

So, what did they do?

They picked 656 students (245 men and 441 women) and gave them a quesitonnaire with some multiple choice questions and some open-ended short-essay questions. The students were given the explanation of the study and guaranteed anonymity. They were given 60 minutes to complete them (I am wondering if this was done in one room at one time or on one-by-one basis). This paper only covers the analysis of one quarter of the overall study (Part IV of their questionnaire).

The average age of men was 21.5 years and for women 22 years. At the time of the study, 89% of men and 77.1% of women reported having sexual experience. Of those, men reported losing virginity at the age of 17.15 years and women at 18.44 years.

The first question was "Do you have dreams with sexual content?" The available answers were "Never of extremely rarely", "Rarely" and "Often". The results for men: 47, 157, 41 (respectively) and for women: 143, 235, 33.

What is troublesome is that after this question, people who answered "never or extremely rarely" were excluded from further analysis. This means that the actual sample sizes for the rest of the study were not the stated 245 men and 441 women, but 198 men and 268 women. I am also wondering what happened: if this was all done in one big classroom (e.g., during Psych 101 class), were the people who answered in the negative to the first question asked to leave the classroom? Those are 20-something students. You can imagine women saying No and men saying Yes (then inventing answers for the rest of the questions) for social-pressure reasons. I wish the paper stated more clearly how was the study done.

The question #2 tried to get a more fine-grained view of the frequency of erotic dreams, dividing the answers over five possibilities ranging from "almost every night" to "once a month or less". Half of the men and three quarters of the women chose "once a month or less".

The third question asked who was the subject of the dream. More than half the men answered "someone unknown", with "my partner" getting only 16.7 percent and other options given very rarely. With women, 102 (37.2%) answered "my partner", 98 (35.8%) chose "someone unknown" and 60 (21.9%) answered "someone known" with all other options ("group", "a relative", "celebrity", "a person of the same-sex" and "unusual partner, e.g., old people, children or animals") given very rarely. If I was designing the questionnaire I would have probably woded some of the options differently, e.g,. "partner of same sex", "partner of opposite sex", "a flame who is, unfortunately, not my partner", etc.

The question #4 asked about the content of the dreams. 77.8% of men and 34.1% of women answered "conventional sex with penetration", 15.2% of men and 60.1% of women chose "kissing and petting" while all other answers were answered quite rarely ("walking, talking or touching", "oral or anal sex", "sexual activities in which I experience pain" and "sexual experience in which I give pain"). OK, but again, I would have done it a little differently, perhaps moving the "feel pain/give pain" to a separate question altogether.

Next question inquired about one's subjective experience and behavior. 44.7% of women and 34.5% of men said "I feel tense", 29.4% of men and 19.8% of women wake up without an orgasm, 10.7% of men and 8.4% of women reported experiencing an orgasm and subsequently waking up, 4.1% of men and 13.9% of women answered "I feel relaxed". I have some problems with the questions/answers as some are not mutually exclusive, yet, judging from the table, participants were required to choose only one answer. I would have split this into two or three separate questions, one asking about waking up and having an orgasm (purely "what happened" questions), one asking about feeling relaxed or tense (the psyhophysical responses), and another for subjective opinions on the experience and emotions.

Question #6 asked "who do you tell about your erotic dreams?". 36% of men and 39% of women chose "nobody", 16% of men and 26% of women chose "to my partner", 39% of men and 32% of women chose "to close friends", and only a very small number of people chose "acquantance" or "physician". Here, I'd let them give more than one answer, perhaps with some kind of way to indicate frequency (e.g., half the time nobody, 25% of the time my partner, 20% of the time best friend, and 5% of the time acquntance, etc.)

But the real kicker comes next, putting under doubt all the data so far. Both men and women without real-world sexual experience have very rare erotic dreams (and since the numbers are small, there is no statistical difference between the sexes). People with sexual experience have sexual dreams much more often and the sex difference becomes very pronounced: 81.2% of experienced men and 66.8% of experienced women have sexual dreams [Note to the Editor: the Table is mislabelled to say "inexperienced", where it is clear from the text that it should read "experienced"]. I guess one can dream only about familiar things and no amount of watching porn can substitute for real experience.

One can think of numerous ways the difference between experienced and inexperienced people could have affected the results of previous questions (I wonder why didn't they do a separate analysis for the two categories!?). If you are inexperienced, it is likely you do not have a partner so that answer is out for this group of people and they have to choose something else.

If you are 20 years old or so, it is likely that you are head-over-heels in love with someone who does not return the love (remember the intensity of feelings when you were that young?). If a subject dreams about that person, will the answer be "my partner" ("oh, how I wish it was true...") or "someone I know"? If you are inexperienced, is it more likely you will dream about "walking, talking or touching" and "kissing and petting" than any other option? Would you be more "tense" if you don't really know how sex feels, and more "relaxed" if you do? All those things could presumably be figured out from the data they have and should have been included in the paper.

Interestingly, the Discussion starts with the lament that most of the scientific literature is concerned with 'why' we dream and not with 'what' we dream, leaving the latter topic to the Old Wives' Tales and pseudoscience peddlers. On the other hand, sleep research is more concerned with 'how' we sleep than 'why' we sleep.

Their data (more men than women have sexual dreams and men have more frequently such dreams) is explained by the menstrual cycle (once a month) for women and circadian rhythm of testosterone (once a day) for men, which makes no sense. Why should hormonal surges have anything to do with dream content? And, if I remember correctly (literature on humans is not at my fingertips like the avian is), the testosterone peak is very low (i.e., the amplitude of the rhythm is small) and it appears in the morning, thus presumably not affecting what is happening during the night. They take this interpretation as favouring a more biological explanation for dreams as opposed to cultural.

The second argument they use to bolster their case for Nature over Nurture is the high concordance between their results and Kinsey results. Whatever discrepancies exist, they explain away by the differences in methodology (e.g., Kinsey asked men about nocturnal emission irresepective of dreams, while they asked about nocturnal emissions only as sa subset of quesitons about dreams), or differences in the age of subjects (Kinsey covered several age groups, not just 22-y-olds), or differences in geography/history/culture. What is left is that men have more dreams than women (as in their study) and they argue that this means the pattern is universal, thus biologically determined.

But wait a minute! Kinsey did his studies in 1948 and 1952, one of the peaks of patriarchy in the US history. The current study used subjects from the Universities of Nis (Southern Serbia) and Podgorica (Montenegro) at the end of 1990s where wars and sanction ushered in a local peak of patriarchy as well (those tend to come right after wars, I guess), in already highly patriarchal (Mediterranean macho-style) society. Furthermore, they did not use the students from Nis and Podgorica (mid-size towns, quite large for that part of the world) who may be more modern and less patriarchal and who tend to live with their parents while attending the University. They questioned only students who live in the dorms - those are not kids from Belgrade, but kids from surrounding small towns and rural areas that are even more traditional and patriarchal. And, as much as living in the dorm is a life-changing experience, I doubt that by the age of 22 or so they all managed to shed all of their patriarchal upbringing.

Then, they argue that the difference between inexperienced and experienced subjects is due to their rates of psychophysical development and maturation, as if this correlates with the date of losing virginity, i.e., once you reach a particular level of physical maturation (hormones and such), you immediatelly go and get laid. Really? Perhaps in other animals, but not in humans.

Finally, they argue for a biological determination of sexual dreams because there is great similarity between these data and the data of their other study not yet published at the time (it came out a year later - I have it and will review it), on the prevalence of sexually-themed daydreaming. They argue that we can exert a greater control over daydreams than dreams, so the similarity in frequences must be due to biology? How? Doesn't it say the opposite - if we have control (presumably guided by the culture) over daydreams, then having the same frequency of dreams suggests that dreams themselves are affetced by culture. And how can one make such a strong statement by using a study nobody has seen yet at the time (including peer-reviewers).

To their credit, they conclude that while frequency and sex-differences in sexual dreams is biologically determined, the content (and the rest of it, e.g,. who they tell afterwards, how they feel about it, etc)., are influenced by culture.

Now, I really trashed the paper, but actually it is not as bad as I portrayed it. I, blogger-style, focused on weaknesses because they are fun to debunk. Obviously from the reading this, though, these are serious, smart, dedicated and professional researchers. So why did they produce a weak paper? I think the answer lies in the List Of References!

There are only 19 references total! Two are to Kinsey reports (male and female). Freud's 'The interpretation of dreams". Jouvet's book on sleep and dreams. A local book on interpretation of dreams that does not sound scientific. Nikola Rot's 1966 textbook on the Psychology of Personality, from which my brother studied (in class taught by Rot himself) back in the 1980s. I would expect that psychology of personality has made some advances in the past 40 years. Then, there are several other books (some in English, some in Serbian, some in translation). A conference paper. Several papers in Serbian. Only a couple of papers in English. Everything quite ancient, too.

I would venture a guess that this study would have been much better designed, performed, analyzed and written if these researchers had access to the literature! If they could read papers in their field, online or off, as soon as papers get published, they would have had a much better scientific mindset, not just a much greater knowledge-base. It is people like them, smart and enthusiastic, but unfortunate to live outside the West, who suffer the most from the Closed Science. It is a hundred times more important to them than to us - and it is darned important to us - that science be made Open.

clock Fri, 04/10/2009 - 21:25

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Friday Weird Sex Blogging - Ladybugs

clock — Sat, 11 Apr 2009 01:21:00 +0000

Friday Weird Sex Blogging - Ladybugs

[First posted here] Since I already posted, earlier in the week, the weirdest and most disgusting animal sex post ever, instead of writing a new one, I'll just send you to see some cute ladybug sex (scroll down to the middle of the post), which also reminded me of these pictures I discovered a few months ago. Or another one, picked up randomly on the web:

clock Fri, 04/10/2009 - 21:21

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Friday Weird Sex Blogging - The Giant Stinkin' Phallus!

clock — Sat, 11 Apr 2009 01:19:01 +0000

Friday Weird Sex Blogging - The Giant Stinkin' Phallus!

{First posted here]. Well, this Friday Weird Sex Blogging is not going to be so unique. After all, Janet and Zuzu have already blogged about it, but who can resist a phallic-looking, rotten-meat smelling, fly-attracting flower! And it is not a B-grade movie on the sci-fi channel. This is real! The Titan Arum (Amorphophallus titanum), in all its 3m tall glory is about to start stinking up the greenhouse at the Brooklyn Botanical Garden (follow the flowering on the blog or watch the flowering web-cam here) :

clock Fri, 04/10/2009 - 21:19

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It's actually a whole inflorescence; the individual flowers actually aren't very big. The largest single flower is a Rafflesia, which also is a carrion flower, but the plant is a parasite. None the less the titan arum is a great thing to behold. I made the mistake of letting a smaller species flower in our house one winter. Smelled like someone had dragged a dead cow inside.

Friday Weird Sex Blogging - Losing Your Head For Love

clock — Sat, 11 Apr 2009 01:16:49 +0000

Friday Weird Sex Blogging - Losing Your Head For Love

As always, animal porn is under the fold (first posted here):

You have probably heard that a female praying mantis eats her mate's head during the mating process. You may imagine the process to go something like this:

Actually, there are many species of praying mantises and in most of them sexual cannibalism is quite rare. It occurs much more often in the laboratory than out in the field. Apparently, the lights and sounds of a laboratory are stressful to the female so she acts aggressively in response.

The praying mantises are very aggressive predators and they can eat quite a lot of food, preferring soft-bodied insects (like flies), but not turning their heads away from cockroaches, snakes....

.... or other mantises, including males of their own species:

The male may be eaten before, during or after the copulation. Male is a great source of protein, so eating him afterwards makes sense for the female:

In only one species, the Mantis religiosa, does it appear that decapitation of the male actually may be neccessary for successful copulation. The removal of the male's head triggers reflexive copulatory motions, resulting in faster ejaculation - why that increases females's fitness is not clear.

A female may eat a male before copulation, especially if she is hungry, the male is small and it is early in the breeding season - he is worth more as food than as sperm donor at that stage.

Videos from out in the nature, though, more often than not, show elaborate mating behaviors and successful escape by the male afterwards. Sometimes they may even engage in a threesome:

While in some other animals there is an advantage for the male to be eaten after mating, such an advantage was not shown in praying mantises. A recent study shows that male mantids prefer not to be victims of sexual assault after all. But sometimes, when she is hungry and you are a lousy lover, that is what you get....

More information here, here and here.

clock Fri, 04/10/2009 - 21:16

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The perfect lover is one who turns into a pizza at 4 AM.

--Shelley Winters

Friday Weird Sex Blogging - Penis Fencing

clock — Sat, 11 Apr 2009 01:15:40 +0000

Friday Weird Sex Blogging - Penis Fencing

Some flatworms, for instance these pretty Pseudobiceros hancockanus, engage in penis fencing. Both individuals are hermaphrodites, i.e., have both male and female organs. The penis is white, pointed and two-headed. Both individuals are trying to inseminate the other. The one who is inseminated has to bear and lay eggs - a more expensive proposition. The one who "won" the fencing bout and did the insemination can move on and fence some other guys and on and on, "fathering" many progeny until happenning onto a better fencer, getting inseminated, and spending the rest of the life as "mother".

clock Fri, 04/10/2009 - 21:15

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Friday Weird Sex Blogging - The Birds Do It....

clock — Sat, 11 Apr 2009 01:13:15 +0000

Friday Weird Sex Blogging - The Birds Do It....

You should check out all of my SiBlings' Friday Blogging practices, then come back here for a new edition of Friday Weird Sex Blogging. Last week you saw an example of a corkscrew penis. But that is not the only one of a kind. See more under the fold (first posted on July 14, 2006)...

Some birds also have spiral tools. For instance, see this 20-cm penis of an Argentine lake duck (Oxyura vittata) (from this paper: The 20-cm Spiny Penis of the Argentine Lake Duck (Oxyura vittata) (pdf)):

The same author, Dr Kevin McCracken of the University of Alaska, Fairbanks, later found an even longer one in the same species. It was 42.5cm long and the paper was worthy of publishing in Nature: Are ducks impressed by drakes' display? (pdf)

The male may use the brush-like tip of its penis to scrub the sperm of previous mates from the female's oviduct. The press coverage was characteristically spectacular: Found! The longest bird penis ever:

"It's a fascinating bit of anatomy they've discovered here. It really is unusual," commented bird mating expert Dr Raoul Mulder from the University of Melbourne.

What a great opener at a cocktail party! What do you do? "I am a bird mating expert!"

Dr McCracken and colleagues speculate that the giant penis may be an example of 'runaway' sexual selection, where female preference drives male anatomy to ever-greater extremes, as in the peacock's tail.

Dr Mulder believes this may be a bit of anthropomorphising, however. "I'm not fond of the 'nudge nudge, wink wink' comments by the authors," he said.

I am with Mulder on this one. But what does agent Scully think?

The journalist, of course, could not help but introduce some more double-entendres:

The authors write that this species is "promiscuous and boisterous in their sexual activity", which means that there is likely to be stiff competition by drakes to be the father of ducklings.

In most bird species, there are no copulatory organs and the two animals just touch their cloacal openings and exchange sperm. The female is capable of storing sperm and choosing which male's sperm to use to fertilize her eggs. The species which do have penises, thoughs, include some ducks and swans that engage in what appears to the human eye to be "forced" copulation.

The Argentine lake duck, although a holder of the Guinness World Record for length is not the only bird with a penis, or for that matter a bird with a most unusual penis (or a similar organ in a similar place with a similar function). Though only about 3% of bird species have a copulatory organ, some are downright weird.

Here is a little bit more on the topic:

Bigger birds, including ducks, geese, swans, ostriches, cassowaries and kiwis continue to have a penis. This penis is generally spiral in form so that it can reach the female sex opening, which lies to the left in the cloaca. The rhea has an extrudable organ. As waterfowl sometimes copulate in water, the penis helps ensure that the water does not wash away the sperm. The Australian blue duck, for example, has a penis so large that when it finishes copulating the bird has to turn on its back and stuff its penis back into its cloaca.
------------snip-----------------
The male cassowary has an organ that looks remarkably like a penis. This phallus does not discharge semen internally. It is "invaginated," having a tube-like roll of tissue that opens at the tip of the "penis", but is not connected internally to the male reproductive organs. The male's vagina-like cavity is used to retract the phallus by turning it "inside out" (so the non-erect "penis" resembles the finger of a glove pushed inward). While the male inserts his erect phallus into the female during mating, he ejaculates semen through his cloaca, an orifice at the base of the phallus that also doubles as the bird's anus and urinary organ.

Female cassowaries mate, lay eggs, defecate, and urinate all through the same orifice, the cloaca, which is exceptionally large in this species, being capable of passing eggs weighing up to 1-1/2 pounds. All female cassowaries also have a phallus, which is essentially identical to the male's phallus in structure but smaller. The "female phallus" is sometimes referred to as a clitoris, but it would be equally valid to speak of a "male clitoris," since the male cassowary's "penis" is not an ejaculatory organ. The cassowary's genital anatomy exhibits a juxtaposition of "masculine" and "feminine" traits: both sexes possess a penis/clitoris and also have another genital orifice that doubles as an anus.
------------snip-----------------
Nature (Vol 399, 6 May 1999) states that male buffalo weavers (Bubalornis) have a false penis or phalloid organ and show intense sperm competition, where unrelated male coalitions defend multiple nest chambers. The organ is a stiff rod of connective tissue, lying anterior to the cloaca. It lacks ducts and is not homologous to the penis in other bird species. Females have a much smaller phalloid organ. The male's organ seems to be a stimulatory organ. After protracted copulation, the organ generates an orgasm-like state in males, unlike other birds.

clock Fri, 04/10/2009 - 21:13

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Friday Weird Sex Blogging

Friday Weird Sex Blogging - Cooling The Balls

clock — Sat, 11 Apr 2009 01:12:18 +0000

Friday Weird Sex Blogging - Cooling The Balls

What?....

There is a slang phrase in Serbo-Croatian that means "doing nothing; being idle; wasting time", and it is "hladiti jaja", which means "cooling (one's) balls". So, if you see a guy just sitting there, clutching a beer bottle and gazing into the distance, you may ask him "Hey, man, whatcha doin'?" and he may reply " 'ladim jaja", i.e., "I'm coolin' me balls".

Well, this slang phrase, indicating a thermoregulatory behavior, has its origin in the real theromoregulatory physiology. Yes, mammals have to cool their balls. That is why mammalian testes are located outside the body inside the scrotum.

Many cells, tissues and organs have an optimal working temperature. Some, like muscles, work best at a temperature a little higher than the core body temperature - hence the need to warm up before excercise. Brain cells are particularly sensitive to fluctuations in temperature, especially to heat. That is why large mammals have large sinuses inside their skulls - this is a heat-stroke prevention mechanism.

Mammalian testis works best at temperatures a couple of degrees below the body temperature. At the core body temperature the sperm get overheated and die. That is why, although having testes outside the body complicates development (vas deferens has to loop over the ureter) and exposes a tender organ to harm (ouch!), most mammals keep them outside nonetheless. That is also why, in some places and at some times in history, sitting in a hot tub for an hour every day, was used as a method of male contraception. That is also why tightie whities and tight jeans are looked at as a possible culprit explaining the reduction in male fertility in the Western world over the past several decades. Global warming is next.

Although the average core body temperature of birds is a couple of degrees higher than the average core body temperature of mammals (yup, birds are hot!), the testes in birds are kept inside the body cavity, roughly in the same spot where ovaries are located in females. This in no way reduces the fertility in birds - evolution has struck on a mechanism of sperm development that works best at a higher body temperature. Unfortunately for those of us doing martial arts, evolution is a blind process and never discovered the same mechanism during mammalian evolution. Thus, the scrotum.

Having a week of blogging about manatees and dolphins, made me think about aquatic mammals a lot. If you ever went swimming or got drenched in a rain, you know that it is so much easier to lose body heat in water or when wet, than in air or when dry (convection is faster than radiation).

But, unlike bulls and lions and elephants and men, walking around with their balls dangling, aquatic mammals cannot have their testes outside of their bodies in a scrotum because it would seriously impede their hydrodynamics. Each testis of this dolphin is 0.5 meters long:

So, cetaceans (whales and dolphins), pinnipedians (seals, sea lions and walruses) and sirenians (dugongs and manatees) have evolved a different mechanism for cooling their testes - the vascular heat-exchanger. This is nothing new in evolution - heat exchange mechanisms just like this are used by many animals whenever there is a need for regional heterothermy, i.e, for some body parts to be warmer or colder than the rest of the body. So, what is the principle on which heat exchangers operate? It is called a "counter-current" mechanism and it works roughly like this:

Blood, warmed by its passage through heat-producing organs (intestines, liver, muscles, lungs, heart) enters the aorta and from there goes to arteries that take blood to all parts of the body. If this warm blood comes to the surface and enters skin capillaries, the heat is dissipated into the environment and there is a net energy loss for the animal. This is something an animal may need if it is overheating, e.g., during exercise, but in general it forces the animal to eat more, thus forage more, thus spend more time exposed to predators and spend even more energy chasing prey.

So, in many animals, the veins that bring cool blood from the skin surface back into the body are located tightly next to the arteries that take blood from the body to the surface. When a warm object and a cold object are close to each other, heat exchange occurs - the warm object gets a little cooler and the cold object gets a little warmer. This is what happens to blood going through these vessels. As the warm blood in the artery encounters the cold blood in the adjacent vein, it cools a little. Further out, it encounters even colder venous blood and gets even cooler. Closer to the surface and it encounters even colder veins and gets even colder. Finally, once it reaches the skin, the arterial blood is as cold as the outside environment. No heat energy is lost. After branching out into the capillaries (in order to exhange materials and gasses with the skin cells), blood enters the veins and goes back into the body, getting warmer and warmer as it receives heat energy from the adjacent artery. Once it reaches the trunk, it is again at the core body temperature and no net energy loss was recorded.

Here it is in a little bit more detail of a dolphin flipper:

As you can see, on the top of the graph is the situation in which all the venous blood passes by the artery. At the surface the blood is cold so no energy is lost. On the bottom of the graph is a situation when an overheated animal needs to lose some heat energy to the environment - the venous blood is shunted to the surface veins instead of the deep veins. The arterial blood does not get cooled as much and reaches the surface while still warm. The heat is lost to the surrounding water (or air). The veins now carry warm blood and they are located at the surface, thus losing additional heat energy to the environment.

The same mechanism is used by wading birds to cool their legs so as not to lose heat energy that way. The same mechanism is used by large tropical mammals (e.g.,. giraffes and antelopes) to cool their brains. The same mechanism is used in the whale tongue in baleen whales - they keep their mouths open all the time and would thus lose a lot of energy as heat via tongues, necessitating even more foraging and eating to replenish that energy. This is how tuna warms up its swimming muscles, brain and eyes and how seals cool off their flippers and tails. This is how Dimetrodon and Stegosaurus are thought to have cooled their large bodies - through the sails and plates on their backs. Even in our arms and legs, the same mechanism operates to a small extent as blood passes through surface veins when we are hot and through deep veins adjacent to the arteries when we are cold.

And it is not just heat that is controlled in the same manner. The same counter-current principle is used in avian lungs to extract as much oxygen out of the air as possible, in avian and mammalian kidneys to concentrate urine as much as possible, and in fish swim bladders to fill or empty the swim bladder.

But back to dolphin balls now! A group of marine biologists at UNC - Wilmington has studied this problem in dolphin, seal and manatee testes and published a series of papers demonstrating that the counter-current heat exchanger - a set of arteries surrounded by many little veins - lowers the testis temperature in relation to the rest of the body. If you have a subscription to "American Scientist" you can read a cool popular-science article on their work in Reproductive Thermoregulation in Marine Mammals:

First, they measured the temperature in the area of the intestine adjacent to the testis while heating and cooling the fins:

A rectal probe housing a linear array of five copper-constantan thermocouples was designed to measure colonic temperatures simultaneously at positions anterior to, within, and posterior to the region of the colon flanked by the countercurrent heat exchanger. Colonic temperatures adjacent to the countercurrent heat exchanger were maximally 1.3Â°C cooler than temperatures measured outside this region. Temporary heating and cooling of the dorsal fin and flukes affected temperatures at the countercurrent heat exchanger, but had little or no effect on temperatures posterior to its position.

Then they measured the temperature of the area during exercise:

A rectal probe housing a linear array of seven copper-constantan thermocouples was designed to measure colonic temperatures simultaneously at positions anterior to, within and posterior to the region of the colon flanked by the CCHE. Immediately after vigorous swimming, temperatures at the CCHE decreased relative to resting and pre-swim values: post-swim temperatures at the CCHE were maximally 0.5 degrees C cooler than pre-swim temperatures. These data suggest that the CCHE has an increased ability to cool the arterial blood supply to the testes when the dolphin is swimming. This ability could offset the increased thermal load on the testes is an exercising dolphin.

Finally, they provide anatomical evidence for a countercurrent heat exchanger associated with dolphin testes:

Cetaceans possess cryptic testes that lie within the abdominal cavity, that are surrounded by primary locomotor muscles, and that are presumably exposed to core or above core body temperatures. It has remained a question as to how cetaceans produce and store viable sperm at these high temperatures. We offer anatomical evidence for a two layer arterio-venous countercurrent heat exchanger at the cetacean testis. Subcutaneous veins from the peripheral surfaces of the dorsal fin and flukes carry cool blood from the fins to the lumbo-caudal venous plexus. The lumbo-caudal venous plexus is juxtaposed to the spermatic arterial plexus, which supplies the testis. Venous plexus flow is from the ventro-lateral margins of the visceral cavity towards the vena cava. Arterial plexus flow is from the aorta towards the ventro-lateral margins of the visceral cavity and into the testis. The existence of a countercurrent heat exchanger suggests that cetaceans potentially compensate for detrimental effects of core temperatures on sperm viability and storage by regulating the temperature of blood flow to the testis.

So, blood cooled at the surface of the flippers and the dorsal fin takes the cold blood into the body and, on its way there, hugs the spermatic artery. The heat exchange occurs in which venous blood warms up, while the arterial blood gets cooled before entering the testis.

This arrangement of blood vessels is consistent with the fact that all aquatic mammals evolved from large terrestrial mammals. Thus, their testes used to descend into a scrotum and dangle outside, then gradually evolved to remain within the body cavity, taking all the associated blood vessels with them.

The group is now looking at the females - do their uterus and the fetus within it also get cooled by a counter-current heat exchanger:

Bottlenose dolphins possess a specialized vascular structure called a counter-current heat exchanger
(CCHE), that functions to cool their reproductive tissues. Heat is transferred from the warm arterial blood to the
relatively cool venous blood at a reproductive CCHE site in the reproductive tissue. This allows cooled arterial blood
to supply the intra-abdominal testes and the pregnant uterus. To test whether CCHE functions to also deliver
relatively cooled blood to the fetus, the following methods will be employed: 1) determine the position of the CCHE,
2) take body temperature at two positions (one at the CCHE and the other at an area unaffected by the CCHE), 3)
maintain a log of deep body temperature over time, and 4) collect other husbandry and health data.

So, next time at the beach when you ask a dolphin "Whatcha doin'?" you may get a response "Coolin' me balls, man!" Or at least you will imagine having such a conversation.

clock Fri, 04/10/2009 - 21:12

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Friday Weird Sex Blogging

Friday Weird Sex Blogging - Corkscrewing

clock — Sat, 11 Apr 2009 01:11:03 +0000

Friday Weird Sex Blogging - Corkscrewing

You really think I am going to put this above the fold? No way - you have to click (First posted on July 7, 2006):

Today's lesson is on the reproductive anatomy of the domestic pig (Sus scrofa domestica), which probably applies to the wild species in the pig family as well. Although we may reflexively think about invertebrates when pondering diversity of copulatory organs, mammals are not too bad in that department either. After all, the sperm is delivered in some species into the vagina (e.g., dog), in others into the cervix (e.g., pig) and in yet others into the uterus (e.g., horse), so different strategies are needed for different goals.

Here is a schematic of the reproductive organs of the pig:

Here is an excerpt from a scientifically worded online description of the sow's cervix:

The cervix is approximately one inch in diameter and about 6-8 inches in length, and connects the vagina and the uterus. It is made of tough connective tissue and contains limited amounts of glandular and muscular tissue. It contains a series of five interdigitating pads (Figure 1) which provide pressure points for locking of the penis (or AI catheters). Its primary functions are to serve as a locking mechanism for the penis. The cervix is also a flexible structure and can open and close under the influence of hormones. The cervix is important for protecting the fetuses and will remain tightly closed except at estrus and at farrowing, when it will dilate to accommodate the boar's penis and to allow passage of the piglets through the birth canal. The cervix is also the primary source of mucus. Under estrogen stimulation, such as that which occurs at estrus, the mucus becomes watery and can sometimes be seen seeping from the vulva. This mucus serves as a lubricant for the penis of the boar. Under progesterone stimulation during pregnancy, the cervical mucus will thicken and form a plug to prevent any contaminants from entering the sterile uterine environment. This cervical plug will dissolve just prior to farrowing.

And here is an even shorter excerpt of the boar's penis (you CAN click on the link above for additional information, it's OK):

.....snip.....
The extension of the penis causes tension in the fibroelastic tissues of the boar penis and causes twisting of the free end of the penis to form a corkscrew shape. The corkscrew shape is perfectly formed to match the patterns of pads inside the female's cervix. Upon erection and intromission of the penis into the cervix, the locking of the penis into the cervical pads is associated with pressure. This pressure stimulus is needed to induce the ejaculation reflex in the boar.

So, to translate....boar has a corkscrew penis and the sow has a corkscrew cervix. The two are a perfect fit. If you take the two organs preserved in formaldehyde (thus stiffened), you can actually screw the penis into the cervix (we did it in vet school way back when...). Now you know where the slang term for sex comes from...

Of course, nobody has taken an MRI of two pigs during copulation (doing it with humans is difficult enough) to make sure what is really happening, but something here does not make sense. We know that the penis does not make several rotations during copulation. We also know that the boar does not spin like a propeller around the sow's hind end either. Thus, there is no way that the penis actually penetrates in a corkscrew fashion. What it likely does is go straight in, crossing each of the cervical ridges one at a time until it assumes the position in which it completely fits inside the groove.

Now, my dirty mind starts working and I remember an old limerick about Clarence Cool (...who was born with a spiral tool, etc...it is even less safe for work than the rest of this post, but I can e-mail you if you are interested) and his sad predicament, wondering if handedness may be important. What if the boar's penis has a right-handed twist and the sow's cervix has a left-handed thread?

This is the problem with some species of snails, after all:

dextral and sinistral snails have a hard time mating with each other. In some species with low-spired shells, it may be impossible to have cross-chiral matings.

In those snails, the difference is under the control of a single gene.

Something like chirality is likely to have a simple genetic control in the early development of the pig as well, allowing for a small mutation to completely change the handedness of the reproductive system. Will it be possible for the two pigs of opposite handedness to mate? And if not, would that be a pre-fertilization reproductive barrier leading to instant speciation?

clock Fri, 04/10/2009 - 21:11

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Friday Weird Sex Blogging

In the process of hardening during copulation the penis probably corkscrews into place as it takes it's shape to fit into the cervix.

I can vouch for it. I had a degree in animal science and I took a whole semester of farm animal reproductive physiology and I learned ALL about that. The class even dissected a sow's reproductive system. Amazing.

The best part of that semester, my professor trying to collect sperm from a boar with an old veggie can. No luck.