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Spider sex

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Dave Hayden
253212.  Sun Jan 06, 2008 11:52 am Reply with quote

As a spider keeper I have to correct the statement about spider mating where it refers to the pedipalps as a 'pair of specially adapted legs'.

Spiders have eight legs and 2 pedipalps which are actually 'mouthparts'
"Pedipalpi are a pair of appendages that look like small legs. One pedipalp is attached to each side of the spider's mouth, and they form the sides of the mouth. Each pedipalp has six parts. In most kinds of spiders, the part closest to the body has a sharp plate with jagged edges. The spider uses this plate to cut and crush its food. In adult male spiders, the last part of each pedipalp has a reproductive organ."

I took this from the Portsmouth Reptile and Amphibian Society's Spider Factsheet (

Nick James
261218.  Fri Jan 18, 2008 10:14 am Reply with quote

So, spiders reproduce via oral sex? That's odd. What does that mean for when they bite you?

261326.  Fri Jan 18, 2008 1:42 pm Reply with quote

Dave could correct me, but I think the one about latrodectus species, i.e. black widows, routinely killing the male at any point during coitus is an overstatement and based on observations only of l. mactans, although there are other species in which it occurs to a greater extent.

I have a memory from somewhere that C.N.S. - located in the cephalothorax in spiders - enact some form of -ve feedback on the sexual act. By severing this at moment of climax, a greater force of ejaculation occurs. As long as this ensues the deposit of gametes and contination of the line, in simpler species such as spiders, it won't be such an issue.

261481.  Fri Jan 18, 2008 7:35 pm Reply with quote

We thought of running this as a bit of Gen Ig on the show, but the trouble is that they do sometimes kill their mates, so it's a rather wishy-washy question. Which makes it maybe unsuitable for the TV show, though none the less interesting for discussion on these boards.

Dave Hayden
261623.  Sat Jan 19, 2008 8:52 am Reply with quote

It is a complex subject and very dependant on species.

Spiders of the species Argiope aurantia males completing copulation leads to certain death. The deceased suitor's corpse is then trapped in the female genitalia.

Male spiders possess two pedipalps which in adult males become sexual organs , each of which inflates after inserting into the females genital organs. In 55 out of 100 observed matings the male finished mating by inserting his second pedipalp, the researchers saw that the male immediately became unresponsive and assumed a death posture with legs folded under his body. The male spiders' hearts stopped beating after a few minutes.

There was no obvious sign that the female was responsible for this lethal effect. And any stealthy way of dealing out death was ruled out by the actions of one confused male that stuck his second pedipalp into a mealworm carcass trapped in the web. This cross-species necrophilia also instantly triggered the male's death, showing female Argiope's are not to blame.

This does however prevent the female from mating with any other male - so the males genes are given a better chance of survival.

262126.  Sun Jan 20, 2008 8:06 am Reply with quote

Now that is amazingly interesting - I always thought it was the female spider who killed the hapless male.

Nick James
262369.  Sun Jan 20, 2008 4:29 pm Reply with quote

Jenny wrote:
Now that is amazingly interesting - I always thought it was the female spider who killed the hapless male.

I think that only happens in black widow spiders, but i'm not sure - i'm only 16 and thus only have GCSE education in the subject of biology

737092.  Fri Aug 27, 2010 7:58 pm Reply with quote

Very ineresting, never knew spiders had two mating organs, appendage things. : )l

765965.  Thu Dec 09, 2010 8:38 am Reply with quote

Male redback spiders deliberately backflip into the female's mouth during sex. They benefit from this. See Maydianne Andrade's fabulous work . There is a link to some research on traumatic insemination in some spiders too, like in bedbugs, in which insemination is anywhere pierced through the female's body wall (they don't bother looking for an actual opening). Invertebrates are weird.


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