How’s your 50% chance luck turns out so far?

Anoplogaster

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I often wonder how far offspring move from the sac location over the course of their lives. Much like seed dispersing morphologies promote the spread of genes in plants (and lessen nutrient competition with mom), I wonder if sex ratios somehow play a role in spreading genes in spiders. We already know that mature male tarantulas tend to be highly mobile in search of mates. Would the number of males affect the degree of spread?
 

boina

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This is something I've wondered about. Maybe T's are similar to many reptiles, where the temperature the eggs are incubated in determines the sex? I don't think all reptiles are like this ( I think the term is TSD, Temperature Sex Determination, or something like that), but the ones that are....eggs raised at higher temp, and also really low temps are predominantly male. Those raised in the middle range are predominantly female. You still get a mix of both sexes either way, but alot of times the females that come from high temp incubation (Hot Females) have problems reproducing. That's a pretty basic explanation, because my involvement with this is just that...basic. haha. But I remember it being true.

So maybe the same is true for T's? Or some other factors that help determine the sex of sacs?
Spiders have sex chromosomes, so no, sex isn't determined by temps.

I haven't counted, but my impression is that my sling sex ratio is pretty even. I have, however, bought several "molt sexed females" that have turned out male, which annoyed me to no end.
 

BoyFromLA

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I have, however, bought several "molt sexed females" that have turned out male, which annoyed me to no end.
If such things happen, do you contact the seller, and let him or her know?
 

boina

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If such things happen, do you contact the seller, and let him or her know?
Usually, yes, with varying results. I had an offer to switch the male with a female the seller still had (cool) or got told I had no clue about sexing (not cool).

Best result: The seller immediately sent me a female, completely free of charge, and let me keep the male, too. He seemed genuinely embarrassed about the whole thing and I'm sure it was an honest mistake.

Worst result: I got yelled at that those weren't the spiders he'd sold me and I was trying to cheat him... I had bought two "sexed females" from him and both turned out male... I'm pretty certain that was NOT an honest mistake.
 

BoyFromLA

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Usually, yes, with varying results. I had an offer to switch the male with a female the seller still had (cool) or got told I had no clue about sexing (not cool).

Best result: The seller immediately sent me a female, completely free of charge, and let me keep the male, too. He seemed genuinely embarrassed about the whole thing and I'm sure it was an honest mistake.

Worst result: I got yelled at that those weren't the spiders he'd sold me and I was trying to cheat him... I had bought two "sexed females" from him and both turned out male... I'm pretty certain that was NOT an honest mistake.
I do not like that worst result AT ALL.
 

BoyFromLA

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You are poorly informed if you think your odds are 50%; they aren't.
I wasn’t informed at all actually. That was just my rough guess. At the end of the day, it is fun, and exciting to watch slings growing regardless of my odds, and sling’s sex.
 

Rittdk01

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I wasn’t informed at all actually. That was just my rough guess. At the end of the day, it is fun, and exciting to watch slings growing regardless of my odds, and sling’s sex.
I thought that too when I was new to tarantulas. You don’t know till you know :)
 

cold blood

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I was wondering about that. I know I've heard the phrase, "male heavy species" more than once.

Care to shed some light?
Some are just hard to get females...C. schioedtei for instance...L. violaceopes is another that comes to mind...you might get 10 slings and maybe get one male unless you are really fortunate (IME)...others like P. muticus and GBB seem to have a higher percentage of females...maybe that's still only 50/50 and it just seems good because most species produce more males than females.

Maybe T's are similar to many reptiles, where the temperature the eggs are incubated in determines the sex?
As boina pointed out, this isn't the case...if it were, it would be ridiculously easy to figure out as entire sacs would be of the same gender....I've never heard of anything like that.
Females 51%
Males 49%
That's the percentage for humans if I am not mistaken....just shows, actual 50/50 isn't a common thing, even when you would expect it to be.

I often wonder how far offspring move from the sac location over the course of their lives.
Often not far, but I am sure there are species that spread more easily than others. But take B. vagans for example.....back in the 70's, an orange grove in Florida was found to be home to vagans...its speculated that they were release from the pet trade, but I have also heard speculaton that they were released as a pest control attempt....regardless, after all this time, that colony still exists in that same part of that orange grove...hasn't really spread within that grove, much less across the state.

I wonder if sex ratios somehow play a role in spreading genes in spiders. We already know that mature male tarantulas tend to be highly mobile in search of mates.
I think its that males, to find "new bloodlines", need to do a lot more traveling, and with distance traveled, comes significant losses...they longer they have to travel, the fewer will make it....in these instances, its advantageous for there to be many MMs wandering far and wide to ensure propagation.
 
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0311usmc

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I have a male and female p.muticus. In another 5 years once they mature I am going to try my first attempt at breeding tarantulas. The freaking things are stupid slow growing however and I might have to wait 10 years. If I am still alive and haven't died of old age I will let everyone know the ratio for males and females if I get a good sac.
 

Garth Vader

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Most of mine are babies, so either too small to sex yet. I also seem to be terrible at getting the molts in time to try to figure it out. I'll let you know once I have some actual data on this! :)
 

BoyFromLA

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Most of mine are babies, so either too small to sex yet. I also seem to be terrible at getting the molts in time to try to figure it out. I'll let you know once I have some actual data on this! :)
Mine are mostly slings as well. So I am just crossing my fingers till I eventually get to find out what their sex are.
 

cold blood

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I have a male and female p.muticus. In another 5 years once they mature I am going to try my first attempt at breeding tarantulas. The freaking things are stupid slow growing however and I might have to wait 10 years. If I am still alive and haven't died of old age I will let everyone know the ratio for males and females if I get a good sac.
Keep in mind, that in order to get a ratio, you wouldnt need to just have a sac, but raise every sac mate to a size where they can be sexed....add a few years after the sac is hatched....that would be a daunting task.....not to mention crazy time consuming.
 
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BoyFromLA

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Keep in mind, that in order to get a ratio, you wouldnt need to just have a sac, but raise every sac mate to a size where they can be sexed....add a few years after the sac is hatch....that would be a daunting task.....not to mention crazy time consuming.
Oh my... I only can imagine so many, and many deli cups stacked on top of each other...
 

0311usmc

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Lo
Keep in mind, that in order to get a ratio, you wouldnt need to just have a sac, but raise every sac mate to a size where they can be sexed....add a few years after the sac is hatch....that would be a daunting task.....not to mention crazy time consuming.
Lol. I don't doubt it. I might have to leave it to my grandson because I don't think I have enough years left in my life to raise a sac of p.muticus because they grow extremely slow.
 

cold blood

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Lo

Lol. I don't doubt it. I might have to leave it to my grandson because I don't think I have enough years left in my life to raise a sac of p.muticus because they grow extremely slow.
Right, it would practically take multi-generational research.:astonished:
 

Lil Paws

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I only have 3 sexed from my group. One I bought presexed (the G. Pulchripes) and the other is very easy to sex (the E. Militaris—the tiny jumping spider I found—they are a sexually dimorphic species). I came close to knowing my GBB's sex, but the stinker chewed up her molt. Just from looking at her ventral side I suspect she is a female, though. The others are a really toss up. The A. Avicularia could probably be visually sexed by a more experienced keeper than me, but she's so *hairy*.


Male:
B. Albo

Females:
G. Pulchripes
Eris militaris

Unsexed:
2 B. Vagans
Versicolor
A. Avicularia
C. cyaneopubescens (suspected female)
 
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