I just thought I'd start an official "ventral sexing" thread. If you have both males and females of the same species, post some comparison pics here. If we can build a nice collection of photos for different species, perhaps this thread can be a good reference point.


sexing immature Grammostola aureostriata

male (main photo)
female (insert)

Female on left, male on right side.

Can this please become a Sticky?
This is great info and needs to be readily available for everyone!

Great idea , Anette. Hope we get lots of pics. I've still got some immature females and males I can photograph.

Thanks, tunedbeat, for contributing those nice pokie pics!

Matured female/male,

What should be done is a sticky thats locked from replies. And then just take the posts that are usable in here and place them there.

My retakes are happening tonight and I may even post some as well.

P.S. Man am I itchy

B.klaasi immature male


B.klaasi female



Theraphosa blondi immature male


Theraphosa blondi female

Here's one for now.

Yeah, this is such a dirty, itchy job, but someone has to do it. The thread stays open for as long as it takes to get bazillions of great photos. Keep'm coming.

I've been thinking about starting the thread for a long time....just never got around to it.

Well I took over 200 photos yesterday. Some didn't work out and some are duplicates, but I have atleast 20 different species if not more. Some don't have a male to compare with the female and vice versa but alas I suffered lol. Not to mention my fiance got tagged also (long story and I'm not speaking about it yet lol)

Since I'm new to this I'm trying to make sense of these pictures. It seems the males have a sort of elongated, more oval-shaped genital area and the females are more flat and horizontal? Is there a really good article someone could refer me to?

Thanks,
Payton

The literature that jump-started it all:
'The spinnerets and epiandrous glands of spiders' by B.J. Marples, Journal of the Linnean Society, 46, 310, pg. 209.

And a well-known link that elaborates on it:
http://www.birdspiders.com/faq_sex.html

And a decent article that covers sexing in general:
http://atshq.org/articles/sexing.pdf

The biggest tell is a divot right in the highlighted area look at the T. blondi as a great example. The divot indicates a male 100%. Then look for a good ridge right along the line that is immediately below where the divot would be if it's raised/protruded then it's 100% female. Any shortcomings in ventral sexing come from lack of either indicator or poor camera angle/lighting.

Here's a few more:





This is not a ventral one and if someone wants to get the ventral shots be my guest

Note to anyone wanting to contribute to this. There is a huge difference ventrally between S/A males and mature males. To make this thread all it can be we would be best to have both.

I read the West/Hart article and this seems to be one of the most important statements: "This paper is about spider spinnerets, of all things, and made references to certain fusilla or spinnerets that are found only on male spiders, called epiandrous fusillae. According to the paper, nearly all male spiders, including all tarantulas, have this extra set of silk spinning glands and fusillae . . ." (This refers to Marples paper that West passed out at the conference.)

So I studied the pictures carefully but I'm having a bit of trouble seeing the epiandrous fusilla/spinnerets. I suppose this is something one learns through doing, rather than reading message boards, but if anyone has any pictures where they can more specifically point out the epiandrous fusilla that would be helpful.

Also, forgive my ignorance, but am I correct in understanding that the terms "spinnerets" and "fusilla" are used interchangeably? Is "spinnerets" the more colloquial term?

Thanks so much,
Payton

Payton,
Yes, the epiandrous fusillae are specialized spinnerets, found only on the males.

Until Marples' paper came along, no one in the hobby was aware they functioned as spinnerets. The silk produced is milky white, super-fine. The male tarantula creates a "bullseye" on the sperm web with these specialized glands and then deposits his sperm there.

The hairs/spigots/fusillae/spinnerets can be seen easily in some species....others not. The "not" part is where the fun begins.

Thanks, Rhys, that is helpful.

After you collect a bunch of different pictures for different species it would be nice to put together a nicely organized web page with a short write up that has hints as to the peculiarities and idiosyncrasies of sexing each species, along with the pictures. Perhaps a page on the ATS site?

I'm not web-building savvy, but since I suggested the idea I'd be happy to organize the written information that comes through the threads if you need help.

Can't wait to see those 200 pictures, Trev!

Best,
Payton

That will be a long while coming. The 200 I do have roughly half are crap. Focus was wrong, too little or too much lighting. On top of that some of the left overs are duplicates. Then to top that off I have ventral shots, but no sex to tie it to (ie not confirmed by a molt). It would not be beneficial to go on a limb and say the one B. boehmei ventral shot I have is female and have that be wrong or the H. minax "sexed female" even though it came from a very reputable source mistakes can happen.

Not to mention the A. genic and A. seemani comparisons I put up are fairly useless as they are mature males which look entirely different than sub adults.

I'm not trying to burst anyones bubble, and I am working on it, it's just going to take some time to get it all together with crisp, clear, big photos so that all the detail shows. Not to mention I'm working with a 5 MP point a shoot camera.

And if all that wasn't enough I'm still itchy from last weekend. I even rubbed 2 fingers raw in my sleep it itched that bad.

Note to self: Lasiodora difficillis, A. geniculata, and all the Brachys combined do not make for a good hairing experience.

Matured male on the right, 7" female on the left.