PZ Myers. 2005 Mar 29. Spider Kama Sutra. <http://pharyngula.org/index/weblog/spider_kama_sutra/>. Accessed 2008 Aug 21.

Posted on M00o93H7pQ09L8X1t49cHY01Z5j4TT91fGfr on Tuesday, March 29, 2005

Spider Kama Sutra

I've been savoring this lovely used book I picked up a little while ago, The Book of Spiders and Scorpions by Rod Preston-Mafham, and am appreciating more than the fact that it is full of beautiful photography of spiders and lots of general information on arachnid behavior and physiology; it's also true that spiders are awfully sexy beasts. They are playful and romantic and kinky and enthusiastic and ferocious and savage and exotic, and really know how to have a good time. I thought I'd share a few of the pretty pictures and details of the arachnid sex life with the readers of Pharyngula—so if you're mature enough to handle it, exuberant enough to enjoy reading about interesting animals doing fun things, and aren't too squicked out at the idea of closeups of spider genitalia, read on.

First, a little anatomy, and we'll start with the female. Here is the underside of a generic spider.

spider kama sutra
spider kama sutra

The detail we're concerned with is the epigyne; that is the entrance to the female reproductive tract, and it's in an unsurprising place, the underside of the belly. Over to the right I've included a nice gynecological closeup of the epigyne of Pholcus phalangioides. Isn't it pretty? Epigynes may vary greatly from species to species, consisting of everything from a simple pit to an elaborate plate with bumps and hooks and latches. One mechanism of ensuring species fidelity is to evolve elaborate intromittent organs and complementary vulvae that fit together in a lock-and-key mechanism.

Another feature of the diagram above and an important character for the chelicerates are the mouthparts. The jaw is labeled, with its fangs and crushing/chomping parts, and next to the jaw is unlabeled, segment appendage, the palps. The palps are sensory and manipulatory mouthparts that have another important function—they are the male sex organ. Male spiders don't have penises, and although they do have reproductive organs in the usual abdominal place, they've secondarily modify their mouthparts to do the actual work of mating.

Here, for instance, is a male of the genus Peucetia. The paired green slabs hanging down from his face are the jaws, while the pair of jointed, bristly structures on either side with complicated twisty bits at the end are his palps, which he is probably fantasizing about introducing into the epigyne of a female.

spider kama sutra

Going courting for a male takes a little preparation. Those palps are nowhere near his reproductive tract, so what he has to do is spin a tiny scrap of web and ejaculate a bit of semen onto it; he then dips his palps into it and fills a hollow channel in them. That's right, the prelude to spider mating is for the male to charge his face up with sperm. This can actually take quite a while, a half hour to several hours, so it's an important part of the process.

Another important and dangerous step is flagging down a willing female. Spiders often have elaborate courtship rituals, with fancy dancing, wig-wagging palps, and fragrant pheromones, all working to convince the female, who is a ferocious predator, that the male is friendly and conspecific and wouldn't she like a little wink-wink-nudge-nudge instead of or before eating him? I can sympathize. I remember when I first asked my wife-to-be out on a date in high school, and I was as nervous as if there were a worry that she might sink her fangs into my skull, inject my cranium with digestive enzymes, and slurp my brains out like a tasty oatmeal milkshake. With spiders, they might really do that.

Once the female gives the all clear, what next? Here are some suggestions from The Joy of Spider Sex, a book that doesn't exist but should.

spider kama sutra

Here our happy male is going for the gusto and directly pressing his palps against the epigyne, inserting one after the other and squirting their contents into the happy orange lady. This is effective, but note one awkward characteristic of the position: the male is directly beneath the females jaws. This is also the characteristic position for her meals, and one thing you do not want to do while mating with a spider is remind her of dinner.

Now this is not a problem in many species, in which the female may plan on dining on her paramour afterwards, and in some species, the male will actually spontaneously expire upon completion of the act. Males who plan on having sex more than once, though, may prefer the next position.

spider kama sutra

Here the male is on top, away from those fearsome jaws, and is curling around her side to reach the epigyne with his long and agile phallic palps. This is much, much safer.

This next position requires some long term evolutionary preparation.

spider kama sutra

Some spider species have an unusually elaborate cephalothorax; their back is festooned with elaborate cuticular protrusions and bumps and hooks and bristles. In these cases, the female clamps onto some of these bumps, like the pommel of a saddle, and may be distracted or entertained…it's like he has evolved a collection of sex toys on his back to keep her happy while he diddles her backside.

I know, you don't want diagrams, you want to see the real thing. Here's a pair of Evarcha falcata gettin' wild. Look at the expression on her face—you know she's loving this.

spider kama sutra

Spiders can get a bit kinky, too. This species, Xysticus cristatus, has a solution to the problem of hungry ladies: they practice Japanese rope bondage. The male has wrapped the female in webbing to keep her under control while he dives under her belly to do the deed.

spider kama sutra

Speaking of arachnid mating and sex toys and bondage (clever segue, eh?), the only sex shop proprietress nicknamed after an arthropod that I know, flea of the most excellent weblog One Good Thing, is having a spot of financial difficulty, as I learned on Bitch, Ph.D.. You can help out by browsing their online store, the Honeysuckle Shop, and picking up a few items for your courtship rituals. Despite being named for an arthropod, I notice that she seems to be marketing to an exclusively mammalian clientele (I wonder what a spider sex shop would be like?*), but since I suspect almost all of the readers of Pharyngula are probably mammals, too, it might work out. Anyway, take a look. Think like a horny spider.


*I'm thinking they'd be stocked with palp sharpeners, epigyne wrenches, E-Z-Fast sperm loaders, exotic pheromone waxes, self-adhesive cephalothorax twiddlers, and for the more timid males, a line of tranq rifles.

Posted by PZ Myers on 03/29 at 11:54 AM
Science • Organisms • Weblogs • 0 Trackbacks • Other weblogs • Permalink
  1. Like humans, some spider species also present their females with elaborately wrapped gifts -hapless prey captured in webbing. While the female busies herself with opening the present, the male quickly fertilizes her and bolts.

    Also, the bravest spider males are probably those of the genus nephila, who court gigantic females up to 100 times their own size. Imagine trying to date a dominatrix the size of a shopping mall, ooohh oooh.
    #: Posted by memo  on  03/29  at  12:39 PM
  2. (cough...ahem) You SEE! This PROVES the evils of evilution! Your FAITH in EVILUTION makes you DEPRAVED, DEGRADED ATHEISTS with no SENSE of MORALITY! So you actually find SPIDER PORN exciting! You are all SICK!

    Of course, if you don't mind, I'd like a little bit more of that tentacle porn, please... smile
    #: Posted by  on  03/29  at  01:07 PM
  3. Best. Pharyngula. Post. Ever.

    Woohoo! Who says biologists don't know how to have fun.

    BCH

    PS - Is there some declinsion of "voyeur" that connotes inter-species observation?
    #: Posted by Burt Humburg  on  03/29  at  02:35 PM
  4. Your Honor, Mr. Jackson has no knowledge of how that Spider porn got onto his computer.
    #: Posted by Monty Zoom  on  03/29  at  02:41 PM
  5. "That's right, the prelude to spider mating is for the male to charge his face up with sperm." Thanks for the dating tip, PZ, I'll try that next weekend.
    #: Posted by  on  03/29  at  02:58 PM
  6. This was great. It reminds me of what was the best zoology lecture I ever got. My invertebrate zoology teacher dimmed the lights, put on a CD of Bolero, and began dancing in and out of the room, showing us examples of the different courtship behaviors of some spiders, he as the male, a chair taking the role of the female. It was absolutely hilarious, and yet somehow he managed to do it all with a completely straight face. He was always very careful not to do it when other professors could see him, though. I'm sure they'd have loved to see some examples of spider lovin' too!
    #: Posted by  on  03/29  at  03:08 PM
  7. That other dating tip is much more important: don't remind her of dinner.
    #: Posted by PZ Myers  on  03/29  at  03:13 PM
  8. Argh! So freaky! You're freaking out people are freaked out by spiders! Argh!
    #: Posted by  on  03/29  at  04:14 PM
  9. People who are freaked out by spiders deserve to be outfreaked. They should stop, and learn to love or at least appreciate these magnificent wee animals.

    Great post, PZ. I would say that, of course. I won't concur with Mr Humbug, but only because I find the Best. Pharyngula. Posts. Ever to be those that tell me about things of which I had previously known nothing whatever (and there are a lot of these...). As I've learned a small bit about spiders, this post had, rather than that giddy headspinning rush of revelation, the warm comfort of the familiar. But that's nice too.

    Oh, and DOD, don't think I've forgotten about you, you philistine. PZ has let his famous sense of delicacy elide over one key fact about spider degustation. It's true that some spider venoms have components that start to break down prey tissues. The main point of the bite, though, is simply to stop you moving. For the most part, spiders don't inject digestive enzymes through their fangs; they vomit them into the wound, then suck the soupy mass back up using an impressive structure called the 'sucking stomach'. You're slightly less freaked out now, I trust. To unoutfreak you further: there's a whole family of spiders, the Uloboridae, that entirely lacks venom. They trap their prey on webs and immobilise it with silk, then eat it alive without killing it first. It's as though you strapped a live cow to your dining room table, bit a hole in its side, puked a quart of pepsin into the hole, then drained the cow with a straw. I'm asking you: what's not to love?
    #: Posted by Mrs Tilton  on  03/29  at  04:41 PM
  10. Very cool, PZ!

    Never having been exposed to invertebrate anatomy, I'm curious about some of the familiar terms in the diagram above. Are "maxilla" and "sternum" truly homologues of the vertebrate structures, or are they analogous structures named after the vert structures for convenience? I am not sure that a bone can have an exoskeleton homologue, but maybe it can, if homologous structural genes control their development. I'd like to learn how biologists regard them.

    In fact, if you could refer me to any sources that compare vertebrate anatomy to invertebrate, and (even better!) specifically address questions of homology across such different anatomies, I'd really appreciate it.
    #: Posted by  on  03/29  at  05:03 PM
  11. No, those aren't homologous at all -- spiders are protostomes and vertebrates are deuterostomes, so you'd probably have to turn the beast upside down and backwards to line them up.

    I've got a few things scattered around here -- you could try searching for "bilaterian". Otherwise, you might have to hit the books and look up Raff and Carroll.

    Maybe I'll put something together about it sometime, though.
    #: Posted by PZ Myers  on  03/29  at  05:14 PM
  12. One mechanism of ensuring species fidelity is to evolve elaborate intromittent organs and complementary vulvae that fit together in a lock-and-key mechanism.
    This was my high school biology teacher’s favourite sort of isolating mechanism. She used to delight in describing it as “bits don’t fit isolation” and using constructive examples and diagrams to prove her point.
    #: Posted by David Winter  on  03/29  at  07:33 PM
  13. in some species, the male will actually spontaneously expire upon completion of the act.

    Is there a technical name for this? How well is the process understood?
    #: Posted by Wm Annis  on  03/30  at  08:38 AM
  14. A few years back, the Museum of Natural History had an exhibit on spiders. (Marvel Comics--which publishes Spiderman--was the sponsor.) It featured, among other things, video displays showing spiders in action: building webs, catching food . . . and mating.

    The last one had the crowds. People ignored the rest of the exhibit and watched it repeatedly.

    Some of the men had erections.
    #: Posted by  on  03/30  at  02:31 PM
  15. Pharyngula: you come for the witty ID rebuttals, you stay for the fucking spider pics.
    #: Posted by Tom Morris  on  03/30  at  06:08 PM
  16. Or is it vice versa?
    #: Posted by PZ Myers  on  03/30  at  06:32 PM
  17. Mrs. Tilton:

    It is important to realize that for most people the freak factor is entirely visual. The little heads with the eyes and the teeth/mandible/claws/gaping maws of terror are what freak folks like me out; The legs moving as one...

    I can appreciate the mechanisms and ingenious solutions to the problems all life faces, but boy I don't want to look at it.
    #: Posted by  on  03/30  at  10:32 PM
  18. Hmmm. I feel exactly the opposite: I want to look deep into the ocular apparatuses of the alien. The weirder the better. The anthropomorphic is just a little bit boring.
    #: Posted by PZ Myers  on  03/30  at  10:49 PM
  19. Well, I can admit the green guy at the top is a bit cute; reminds me of Curly. I lose the plot at the next guy.
    #: Posted by  on  03/30  at  11:22 PM
  20. The Huntsman spider is my favorite, very common around most parts of Australia. From http://www.amonline.net.au/factsheets/huntsman_spiders.htm:

    In the genus Isopoda, the male and female Huntsman spiders have a lengthy courtship, which involves mutual caresses, with the male drumming his palps on the trunk of a tree. He then inserts his palps into the female to fertilise her eggs. The male is rarely attacked, unlike some other species, and in fact many huntsman spiders live peacefully together in large colonies. A silken retreat is often built for egg laying, as well as for moulting. Some species of Neosparassus build a silken retreat in foliage, often at ground level, by binding several leaves together with silk, while others construct shallow burrows or move into abandoned cicada burrows.
    #: Posted by  on  04/02  at  07:24 PM