Weird: Scientists discover oral sexual encounters in spiders

Normally, I would not carry a science story like this, but it is just so weird, it seemed worth noting. Those with arachnophobia need not read this.

Darwin's Bark Spider
Darwin’s Bark Spider

Matjaz Gregoric, a research associate at the Scientific Research Centre of the Slovenian Academy of Sciences and Arts (ZRC SAZU), Jovan Hadzi Institute of Biology, and coauthors studied the mating behavior of the Madagascan Darwin’s bark spider (Caerostris darwini), a sexually size dimorphic species from Madagascar with females several times larger and heavier than males. They uncovered a rich sexual repertoire in C. darwini that predictably involved sexual cannibalism and genital mutilation. In addition, their surprising finding was that males of this species routinely salivate onto female genitalia.

“Oral sexual contact seems to be an obligate sexual behavior in this species as all males did it before, in between, and after copulations, even up to 100 times.” said Gregoric who led the field and laboratory work that resulted in the current publication. Matjaz Kuntner, the senior author on this paper and chair of the Jovan Hadzi Institute of Biology ZRC SAZU only recently discovered and described C. darwini, noting that it produces nature’s largest webs and toughest silk. Now, this intriguing finding adds sexual behaviors to the species’ natural history.

Oral sexual contact is rare in the animal kingdom, except in mammals, where fellatio-like behaviors are known in macaques, lemurs, bonobos, hyenas, cheetahs, lions, dolphins and bats. However, cunnilingus-like behaviors, like the one shown in this spider are even rarer. Gregorič and coauthors suggest that oral sexual encounters could be a mechanism for boosting the male’s chances of paternity by either signaling the male’s quality or creating a chemical environment that would favor one male’s sperm against the sperm of rival males.

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April 29, 2016 3:30 pm

Foxtrot Oscar Charlie Kilo.

Reply to  Geoff Sherrington
April 29, 2016 4:43 pm

Shouldn’t that be, Foxtrot Uniform…

Reply to  SMC
April 29, 2016 6:48 pm

Maybe, but I don’t swear in mixed company.

Reply to  Geoff Sherrington
April 29, 2016 6:38 pm

In this case: Whisky Uniform Foxtrot Foxtrot Delta India Victor Echo

Lance Wallace
Reply to  MattS
April 30, 2016 9:01 am

Try Mike instead of Whiskey?

Reply to  Geoff Sherrington
May 4, 2016 7:33 am

What I find amazing is the frequency of the relation of peoples names with the topic. In this case, the senior author’s last name (Kuntner) relative to the spiders’ activity.
Does a person’s last name encourage studying certain topics?

Tom Halla
April 29, 2016 3:30 pm

Nice relief from politics, uh, global warming.

Reply to  Tom Halla
April 30, 2016 1:44 am

I noticed great deal of interest about such practices from readers

Reply to  vukcevic
April 30, 2016 1:53 am

that was suppose to be just an html passive link, didn’t realise it would turn into the animation, delete if necessary.

Gerry, England
Reply to  Tom Halla
April 30, 2016 4:58 am

They’ll probably be along in a minute to say that is it threatened by global warming.

April 29, 2016 3:33 pm

It’s your blog Anthony, do as you feel. I have learned something new today as I do every day here.

Bubba Cow
April 29, 2016 3:36 pm

the raw biological truth – no movie needed, straight to dinner

April 29, 2016 3:38 pm

You can’t get much further from global warming than this!

Reply to  AndyE
April 29, 2016 4:04 pm

This aberration from normal arachnid behaviour is clearly due to CO2 poisoning and high temperatures. Give me a nice big grant and I’ll prove it! I already know how. Make an air tight terrarium, remove CO2 from the air in it, and reduce the temperature enough, and I am pretty sure that the spiders will stop doing this. /sarc

Bye Doom
April 29, 2016 3:41 pm

Canine cunnilingus appears to be normal.

Reply to  Bye Doom
April 30, 2016 4:13 am

yeah…and I have two very “gay”dogs..much facepalm around visitors;-(

Bye Doom
April 29, 2016 3:45 pm

Arachnosex is deadly serious business:
No doubt global warming is causing such unprecedented problems with spider reproduction that it’s much worse than we thought.

April 29, 2016 4:01 pm

…..WTF ??

April 29, 2016 4:12 pm

Sounds interesting – trouble (for me) is that I now I initially doubt anything that science says or scientists have found. With so many calls to stand apart from other scientists and other research, my first thought is that it’s a push to be recognized or have a paper published or needed to gain funding.
My problem, I know. At least they didn’t mention global warming anywhere (to my knowledge).

Pat Frank
April 29, 2016 4:19 pm

One unmentioned advantage of the oral encounters is that the male likely ends up smelling a lot like the female. This could inhibit the cannibalistic meal that often follows mating.
Male spiders that were able to survive mating because they smelled like honey-buns, and could then go on to mate several more times rather than once and then becoming a post-coital snack, would leave more offspring and thus be evolutionarily favored.
One could check this by observing whether a male spider, once out of sight and grasp, spends time cleaning himself off, so that sweetie number 2 doesn’t detect sweetie number 1.

Reply to  Pat Frank
April 29, 2016 5:05 pm

“Male spiders that were able to survive mating because they smelled like honey-buns, …”.
Direct Darwinian selection. You may be onto something,

Reply to  Pat Frank
April 29, 2016 7:35 pm

“They uncovered a rich sexual repertoire in C. darwini that predictably involved sexual cannibalism and genital mutilation.”
Ah yes, the old Catastrophic Arachnogenic Genital Wrecking quagmire.

Reply to  robert_g
April 30, 2016 4:14 am

Roflmao!! a winner:-)

Reply to  robert_g
April 30, 2016 4:52 am

+ a ton

April 29, 2016 4:30 pm

It appears to be anything goes, so here goes.
I have ( I guess) seen the mating ritual of Orb Weaver spiders.
The male creates a swing that lets it touch the female only long enough to do what needs to be done, and not long enough to become her next meal.
Take that for what it is worth 🙂

April 29, 2016 4:41 pm

Was it good for you honey? Yes, you were most tasty.

Reply to  ShrNfr
April 29, 2016 4:42 pm

I should clarify the second sentence as being spoken by the female after she has just eaten her mate.

Reply to  ShrNfr
April 29, 2016 10:14 pm

Gives new meaning to going to sleep after sex.

April 29, 2016 4:54 pm

Don’t try this at home.

April 29, 2016 5:37 pm

Yeah, but did they do this BEFORE we humans started polluting the air with excess CO2?

Green Dragon
Reply to  JohnWho
April 29, 2016 5:44 pm

Don’t cha know? Nothing happened before “we humans started polluting the air with excess CO2” Kinky spider sex is just the beginning.

April 29, 2016 7:12 pm

This is attributable to male’s tactical method for getting his own sperm being used & not another of the female’s copulators. Insects use various strategies to get the female to put out sperm from previous male encounters. Look up “cryptic female choice” & will find decades of entomology investigations on how diverse the female insect tactics seem to be in many different (not all) kinds of bugs. So far appears no videos have been leaked on internet….

April 29, 2016 7:45 pm

Then there’s the bedbug. The males are so eager to mate that they can spear a female with their little spear in random places. The resulting sperm then migrate internally to the right place.

Reply to  higley77
April 30, 2016 5:23 am


April 29, 2016 8:19 pm

“boosting the male’s chances of paternity”… or perhaps signalling that this is a mate and not something to be eaten?

April 29, 2016 8:46 pm

Ahhh the Bill Clinton spider I’ve heard of that one .

James Bull
Reply to  Robert
April 30, 2016 12:12 am

As so often here I have learnt something new and had a good laugh as well.
Thank you all.
James Bull

April 30, 2016 12:10 am

I think it’s highly likely that the male C. darwini performs cunnilingus on his mate so as to avoid being devoured after copulation by an unsatisfied female. Maybe more brutal but kinda like feminist female humans really ….

James Bull
Reply to  Luc Ozade (@Luc_Ozade)
April 30, 2016 12:14 am
Scottish Sceptic
April 30, 2016 12:42 am

Took a while to find a link but … British readers may remember this with fond affection:

April 30, 2016 1:38 am

Ridiculous to interpret this as “oral sex” ffs, for so many reasons.
Humans are weird, especially many scientists, who lose touch with reality

Reply to  Mark
April 30, 2016 7:37 am

Humans find it impossible not to attribute human-like terms and motives to animals, insects, etc. At one time, scientists seemed to try and avoid this, but those days are gone. Anthropomorphism is the new norm and if one argues with it…..

April 30, 2016 1:42 am

orb-web spider Nephilengys malabarensis male spider has detachable junk that can finish the job on it;s old 😀!/img/httpImage/image.jpg_gen/derivatives/article_970/spider14n-1-web.jpg

Reply to  Mark
April 30, 2016 1:42 am

*own stupid autocorrect!

April 30, 2016 1:50 am

An ignoble Prize beckons.

April 30, 2016 4:01 am

Another strange one: “Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but related species in the genus Neotrogla, are the first example of an animal with sex-reversed genitalia.”

michael hart
April 30, 2016 4:16 am

What happens in Vegas…

April 30, 2016 4:18 am

what I would like to see is the supposedly huge webs they spin

April 30, 2016 6:50 am

Obviously this research wasn’t done out of pure scientific voyeuristic curiosity – wait for the grant proposal asking the government to print billions of dollars for the education of young spiders about the dangers of oral/sexual transmission of herpes. If you can’t make them stop, at least you can take the fun out of it and make them feel guilty and doomed.

April 30, 2016 8:15 am

Genital mutilation? Are they Islamic spiders?

Reply to  Pointman
April 30, 2016 5:05 pm

FGM is an African problem not an Islamic one, the countries that have 95% rates of FGM are Christian countries not Islamic.

Reply to  Pointman
April 30, 2016 5:06 pm

and Circumcision is mutilation, and the US has a pretty high rate of that.

April 30, 2016 8:34 am

vukcevic April 30, 2016 at 1:44 am
Jeeezus Cristy, Vuc’s
Will growing up I was the kid who drank a glass a milk before eating.
Grew tall enough, but didn’t fill out much, (anywhere lol).
Earned a nickname from an older sibling, the SPIDERWOMAN.
So much for CIRs (corotating interaction regions).
What I have read recently is that these current sheet crossings, are preceded by density enhancements. And
seems that’s what I have been seeing in our cloud cover around here past couple days.
SOLAR SECTOR BOUNDARY CROSSING (UPDATED): On April 29th or 30th, Earth will cross a fold in the heliospheric current sheet–a vast wavy structure in interplanetary space separating regions of opposite magnetic polarity. This is called a “solar sector boundary crossing,” and it could trigger geomagnetic activity around Earth’s poles. NOAA forecasters estimate a 40% chance of G1-class geomagnetic storms on April 29th.
CHANCE OF STORMS THIS WEEKEND: NOAA forecasters estimate a 50% chance of G1-class geomagnetic storms on April 30th when a CIR (co-rotating interaction region) is expected to hit Earth’s magnetic field. CIRs are transition zones between fast- and slow-moving solar wind streams. They contain shock waves and density gradients that do a good job sparking auroras.

April 30, 2016 9:26 am

wow Anthony
global warming is a hot issue

April 30, 2016 12:53 pm

Thank you for not providing illustrations…

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