How to sex T with molt

[spidergirlasf]

Hi! I'm wondering how ya'll sex your T's with the molt. I've looked at pics of both male and female tarantula molts, and can't see a difference. Also, does the age of the T matter?

Thanks!

 

[EtienneN]

Age does not matter, size matters. To sex with the naked eye, you need your T to be roughly 2.5 inches in diagonal leg span. Now a lot of people say at least 2”, but the internal structures we are looking for are pretty small anyway on a juvie T and I’d say closer to three inches is better than closer to two. Now, time to prepare the moult. Get a plastic tub of warm water and a dollop of Dawn dish soap. Put on gloves so no stray urticating hairs get on you and then gently lay the moult in the water and gently submerge it for a few seconds and then get a small soft tooth brush and gently ‘open’ the moult in the water. Be very gentle! I generally hold my moults underwater for about 5 minutes to get them to unravel. Make sure you don’t rip anything and if it’s not coming along well, just let it sit with the inside part touching the water until it does open up. Then rinse your tub and fill it with clean water to hand rinse the moult. Then take the moult out and lay it on a bed of paper towels to dry. Finally grab some sewing pins and a piece of styrofoam and maybe the toothbrush again. Arrange the moult so that the area inside focusses on the area between the top part of book lungs.

Then you may look for the spermathecae which would indicate a female and would look like a leaf shaped flap. There is also a uterus externus which is part of the darkened area you see there.

 

[spidergirlasf]

Thank you so much! My Ts are about 1-1.5" right now, so I probably won't be able to sex them for a while, but I can't wait!

 

[sasker]

so I probably won't be able to sex them for a while, but I can't wait!

A magnifying glass or a microscope (10x or 60x, not 300x magnification, obviously ) could help you out. Also, I sometimes put a zoom lens on my telephone. Enlarging the picture makes it possible to sex slings that are still quite small.

 

[Thekla]

Then you may look for the spermathecae which would indicate a female and would look like a leaf shaped flap. There is also a uterus externus which is part of the darkened area you see there.

This is not completely right, at least not the way you wrote it, I'm afraid.
The leaf-shaped flap you describe is the uterus externus, the spermathecae, on the other hand, is the part where the female stores the sperm from the male and will look like two little "horns" but can be fused into one single structure as well. This part is very distinctive for a species. For example, I just took some pictures of the moult of my female Homoeomma sp. blue peru, there you can see the "flap" and the spermathecae quite clearly, I think:

0.1 Homoeomma sp. blue peru

• Thekla
• Sep 8, 2019
• 1
• exuviae female homoeomma homoeomma sp. "blue" molt moult sexing sp. "blue" spermathecae uterus externus

I got some IMO decent pictures of my girl's spermathecae and her flap. The moult is about 3...

@spidergirlasf Another great source is here with good descriptions of the parts you're looking for: https://tarantulas.p3kb.com/sexing

@z32upgrader made a great video about the process of sexing a moult:

 

[viper69]

Hi! I'm wondering how ya'll sex your T's with the molt. I've looked at pics of both male and female tarantula molts, and can't see a difference. Also, does the age of the T matter?

Thanks!

Age matters! The vid is already up.

 

[z32upgrader]

@z32upgrader made a great video about the process of sexing a moult:

Thanks for the mention and video share. I now recommend an alcohol-based solution for softening molts instead of soap. I use a generic glass cleaner now as I found soap makes smaller molts disintegrate and tear much more easily.

 

[EtienneN]

Yeah, I see how I was unclear, I always thought the spermathecae were the sclerised things and the uterus externus was the wishbone looking thing above it. I guess maybe that’s the ovaduct? That’s like the T equivalent of Fallopian tubes right? Not sure why I thought that part was the uterus, when it’s just clearly logical it’s the flap if we’re talking about equivalent structures.

 

[Thekla]

the uterus externus was the wishbone looking thing above it.

That's the uterus internus.
Have a look at the link I posted. There's a great schematic drawing of all the parts.

 

[spidergirlasf]

Thanks! Ya'll are super helpful!

 

[EtienneN]

Thank you I’ve bookmarked the link!

 

[Ungoliant]

Hi! I'm wondering how ya'll sex your T's with the molt. I've looked at pics of both male and female tarantula molts, and can't see a difference. Also, does the age of the T matter?

See this thread for instructions and tips for processing and photographing the molt: How to Request Species or Sex Identification.

When I am trying to sex a molt, I search the molt sexing gallery for pictures of the species.

If you're stumped or want a second opinion, you can post a picture in the molt sexing gallery. Always include the size and species.