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When breeding or buying slings what’s the male/Female ratio?

Oursapoil

Well-Known Member
Tarantula Club Member
Just wondering... When breeding or buying slings what’s the male/Female ratio?
Very good question, I wonder if someone has a solid/scientific answer for it as I would love to know for sure myself. I would imagine a 50/50 ratio would make sense but then again my answer is not based and data. This said if you want to see more opinions I found this old thread from arachnoboards: https://arachnoboards.com/threads/s...text=What it means is there,%male, 50% female.
 

Casey K.

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3 Year Member
Tarantula Club Member
Just wondering... When breeding or buying slings what’s the male/Female ratio?

Usually, if you buy slings and want to obtain a higher chance of getting a female, I would buy at least 4. You can always buy more (if I find a deal on 10 lots I will usually buy those and you're almost guaranteed a female in a 10 lot but nothing is 100%). I'm unsure of the ratio of male/female in sacs. I suppose it varies by genus, locality, environmental factors, etc.
 

Oursapoil

Well-Known Member
Tarantula Club Member
Usually, if you buy slings and want to obtain a higher chance of getting a female, I would buy at least 4. You can always buy more (if I find a deal on 10 lots I will usually buy those and you're almost guaranteed a female in a 10 lot but nothing is 100%). I'm unsure of the ratio of male/female in sacs. I suppose it varies by genus, locality, environmental factors, etc.
Sounds like the perfect and quite valid justification to buy a lot more Ts. Let's see if I can swing this by the wife :D
From now on Casey, I will put the blame on you for everything ;)
 

plessey

Well-Known Member
3 Year Member
I don't think anyone has ever actually done a proper study of the sex ratio of tarantula spiderlings. I've read a couple of papers on other spider species and from what I remember, based on multiple sacs, it was pretty much a 50/50 split. Sometimes the sacs had a higher male ratio and sometimes they had a higher female ratio. I've often seen this ratio of 3 males to every 1 female being touted for Omothymus violaceopes ever since they were first introduced into the hobby but I've never seen any data to actually back this up.
When it comes to buying slings then obviously the more you buy the greater the chance you have of getting a female. However saying that, I remember getting a colony of 7 Poecilotheria formosa slings from Ray Gabriel and all 7 turned out to be male :D. It's just pot luck in the end with spiderlings unlike buying "unsexed" sub adults and large juveniles where there is a 95% chance it's male.
 

ilovebrachys

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It's just pot luck in the end with spiderlings unlike buying "unsexed" sub adults and large juveniles where there is a 95% chance it's male.
I agree with you there.. I think we've all been duped at some point buying 'unsexed' or 'suspect females' from sellers who know full well that they are male :(- buying slings is the most enjoyable part of the hobby for me and its lovely watching them grow on if they turn out to be male not so bad as we always try to put MMs back into the hobby whenever possible :) if possible always get as many slings as possible to up your chances.. . Why not? :D
 

WolfSpider

Well-Known Member
3 Year Member
I don't think anyone has ever actually done a proper study of the sex ratio of tarantula spiderlings. I've read a couple of papers on other spider species and from what I remember, based on multiple sacs, it was pretty much a 50/50 split. Sometimes the sacs had a higher male ratio and sometimes they had a higher female ratio. I've often seen this ratio of 3 males to every 1 female being touted for Omothymus violaceopes ever since they were first introduced into the hobby but I've never seen any data to actually back this up.
When it comes to buying slings then obviously the more you buy the greater the chance you have of getting a female. However saying that, I remember getting a colony of 7 Poecilotheria formosa slings from Ray Gabriel and all 7 turned out to be male :D. It's just pot luck in the end with spiderlings unlike buying "unsexed" sub adults and large juveniles where there is a 95% chance it's male.
Wow. That sucks. If sacs are indeed 50/50, you had a 1.6%chance of getting all male, mate!
 

Arachnoclown

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Only the spider gods know. I've done a few hold backs with my last few sacks ive pulled or lots purchased. Here are the results....

30 Tliltocatl sabulosum 13.17.0
20 Poecilotheria ornata 12.8.0
12 Hapalopus sp. columbia 7.5.0
15 Alphonopelm Seemani 1.14.0
10 Poecilotheria metallica 9.1.0
5 Ceratogyrus darlingi 2.3.0
12 Psalmopoeus cambridgei 7.4.1 (1 death unsexed)
5 Poecilotheria rufilata 0.5.0
 

WolfSpider

Well-Known Member
3 Year Member
Only the spider gods know. I've done a few hold backs with my last few sacks ive pulled or lots purchased. Here are the results....

30 Tliltocatl sabulosum 13.17.0
20 Poecilotheria ornata 12.8.0
12 Hapalopus sp. columbia 7.5.0
15 Alphonopelm Seemani 1.14.0
10 Poecilotheria metallica 9.1.0
5 Ceratogyrus darlingi 2.3.0
12 Psalmopoeus cambridgei 7.4.1 (1 death unsexed)
5 Poecilotheria rufilata 0.5.0
Awesome Clownie. I know your data is sparse, but you do offer data. Thanks!

I wonder, if like some animals--alligators and certain lizards, for example--sac temps influence male/female EWL ratio.
 
I agree with you there.. I think we've all been duped at some point buying 'unsexed' or 'suspect females' from sellers who know full well that they are male :(- buying slings is the most enjoyable part of the hobby for me and its lovely watching them grow on if they turn out to be male not so bad as we always try to put MMs back into the hobby whenever possible :) if possible always get as many slings as possible to up your chances.. . Why not? :D
I promised myself I wouldn't respond to a third thread, but this was just too good to resist.

Marguerite (now deceased) and I were deeply involved in the pet industry at a variety of levels for quite a number of decades, so I know what I'm talking about here.

Consider a tarantula dealer at some weekend reptile extravaganza. (For simplicity's sake, I'll assume this individual is male, but this story really isn't about human genders. I'm just trying to keep this discussion as simple as possible.) Our dealer friend has a collection of 200 tarantulas on the table before him, hawking them to anyone who'll look his way. We will assume that his tarantulas are equally divided between male and female, 100 males and 100 females, i.e., 1:1.

A customer walks up to the booth and announces he wants 10 tarantulas, but because he's buying them in quantity, he wants to specify that they all be females. Can the dealer fill the order? Of course he can! Business has been slow and he's worried about running out of gas on the way home. "Come back in a couple of hours and I'll have them for you."

At that point he turns the running of the booth over to his helper, grabs several handfuls of tarantula containers and retires to a back corner with various instruments including a dissecting microscope.

An hour later he resurfaces with 10 guaranteed female tarantulas. His customer returns, the transaction is consummated, and the customer disappears into the crowd. At that point in time our dealer grabs the dozen or more tarantulas left from his sexing operation (now assumed to be all males since he just sold the females in the batch) and replaces them on the table among the other, remaining tarantulas.

(Bear with me. I know this is complicated, but it's important!)

Suddenly, he gets a genius idea. He quickly scribbles up a sign advertising guaranteed female tarantulas at a slightly higher price than run-of-the-mill, pay-your-money-and-take-your-chances. And he succeeds in selling another 15 guaranteed female tarantulas (but absolutely none others) by the end of the day.

Now you walk up to his table and ask how much three tarantulas would cost, and he quotes you the standard price per each times three. And you're thinking that there's a fifty-fifty chance of getting either sex with each tarantula, and therefore by the laws of probability, you have seven chances out of eight of getting at least one female tarantula out of the three. You pay your money and leave with your new tarantulas.

What's wrong with this picture?

First off, how did I get that seven chances out of eight malarkey? Well, according to the laws of probability and statistics, there are eight, and only eight, possible combinations among the three tarantulas that you purchased, namely -

M M M
M M F
M F M
F M M
F F M
F M F
M F F
F F F

And the only combination of the eight that doesn't include AT LEAST one female is the first! Thus you have seven chances out of eight of getting AT LEAST one female.

Or do you? Remember that this whole story was predicated on the assumption that the sexes occurred in equal numbers: 100 M and 100 F, 1:1.

But at the end of the day when you finally walked up and bought your three tarantulas, that fifty-fifty ratio was a fiction! The dealer sold 25 guaranteed females out of the lot of 200. Therefore, he still had 100 males, but only 75 females! The ratio is no longer 1:1, but rather 4:3.

And our dealer friend will do the same thing the next day, so by Sunday evening just before he goes home, his inventory numbers 100 males and 50 females, 2:1.

So, by the time I show up to buy my three tarantulas at the last moment on Sunday, I'm being cheated royally!

But all this begs the question of what remedies do we and the dealer have?

My remedy was that once I learned that a dealer was selling guaranteed females, I'd go to a different dealer who wasn't.

To be completely ethical, what might the dealer have done? One dealer I know of charged a surcharge for guaranteed females, and discounted the guaranteed males. Other options include keeping the extra males until they died of old age (a bad business plan), or euthanizing them (one would hope humanely).

The default plan , the one I used, was to play ignorant, "I have no idea what sex they are. Because of the difficulty and uncertainty of sex determination, especially in babies, we don't even try to determine the sex of the tarantulas we sell."

I am very interested in hearing the responses from enthusiasts, vendors and dealers, and maybe even wholesalers, alike. Fire away! I have both a tough hide to ward off blistering attacks, and broad shoulders to cry on.
 

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Arachnoclown

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Tarantula Club Member
Personally I sell slings as unsexed in large lots. Usually at 2nd instar before they need to be separated(100+per lot). I hardly ever sell singles but when I do they are unsexed.
Hold backs from sacks I've produced or lots purchased for myself I sex by molt only. I raise them till I can sex them with a hand held magnifier. I will sell my extra sexed individuals or loan out. Confimed males and females I will sell with last molt or photos.
Im kinda disturbed thinking people let the males just wither away. I personally have financed my entire hobby in the last 38 years from male spiders. I actually enjoy the males as much as the females...maybe more?
 

ilovebrachys

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Im kinda disturbed thinking people let the males just wither away. I personally have financed my entire hobby in the last 38 years from male spiders. I actually enjoy the males as much as the females...maybe more?
Couldn't agree with you more about enjoying keeping the MMs and about people letting them wither away - it's such an waste, put your MMs in the hobby for the hobby sake and breed so more can enjoy the Ts...
I struggle to get my head around when people end up with an MM and insist on finding a AF to go pair up with it instead of just letting the MM go? As ultimately the MM may end up dead and gone before they find a female I dunno maybe I just think differently lol ;)
 
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