Sperm storage, survival and fertilization?

aphono

Arachnobaron
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The comments on disappointments of bred tarantulas molting got me to wondering...

How are sperm stored- do they sit in the spermathecae with no hydration or nutrient aid from the female(seems that way, if they are shed with the exuviae)? How long do they survive(if molt does not happen)? If they are sitting in the spermathecae all by their lonesome selves, what is it that triggers their action/release during egg laying?

Is it possible for a female to produce egg sac with no mating? In birds, mating is not necessary for egg production.. wondering if it's the same for them or not.
 

Nightstalker47

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The comments on disappointments of bred tarantulas molting got me to wondering...

How are sperm stored- do they sit in the spermathecae with no hydration or nutrient aid from the female(seems that way, if they are shed with the exuviae)? How long do they survive(if molt does not happen)? If they are sitting in the spermathecae all by their lonesome selves, what is it that triggers their action/release during egg laying?

Is it possible for a female to produce egg sac with no mating? In birds, mating is not necessary for egg production.. wondering if it's the same for them or not.
It is possible for them to produce phantom sacs, meaning the eggs aren't fertilized, and will never develop. It happened to me with a large WC female Hysterocrates sp. Cameroon, she molted twice during my care and eventually just produced an egg sac, I had never bred her.

I was very surprised to find her with a sac, but I knew it was impossible for it to carry viable offspring. I'm not sure how often this happens but it's definitely interesting, here's the pics I got of her and the egg sac.
 

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aphono

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That's a beautiful specimen!

Phantom sacs are more the exception than the rule? That kind of seems to hint at mating as an important trigger for egglaying or is there something else I'm not aware of?

Too bad there was no chance for fertile eggs, would have been nice to bring more genetic diversity into the hobby- father(s) not present in the captive population..
 

EulersK

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I can't speak for tarantulas, but I have a black widow that just laid three sacs. I caught her as a mature female about a year ago, and at least one of those sacs is viable. So it seems like they can keep the sperm alive almost indefinitely.

I personally think that sacs are triggered one of two ways: mating or proximity to males. About six months ago, I just happened to be sitting on six MM's and all were obviously tapping nightly. Within a couple months, I had three phantom sacs on my hands.
 

Nightstalker47

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I can't speak for tarantulas, but I have a black widow that just laid three sacs. I caught her as a mature female about a year ago, and at least one of those sacs is viable. So it seems like they can keep the sperm alive almost indefinitely.

I personally think that sacs are triggered one of two ways: mating or proximity to males. About six months ago, I just happened to be sitting on six MM's and all were obviously tapping nightly. Within a couple months, I had three phantom sacs on my hands.
But the MF black widow never molted right? I would assume that the molt would cause it to lose the sperm, the same way it would with a tarantula. I wonder what would trigger the spider to make phantom sacs,that bit about the males was very interesting, as my female H.sp Cameroon built her sac just about when I had another MM Hysterocrates sp. mature. And they were housed in close proximity to each other...
 

aphono

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I can't speak for tarantulas, but I have a black widow that just laid three sacs. I caught her as a mature female about a year ago, and at least one of those sacs is viable. So it seems like they can keep the sperm alive almost indefinitely.

I personally think that sacs are triggered one of two ways: mating or proximity to males. About six months ago, I just happened to be sitting on six MM's and all were obviously tapping nightly. Within a couple months, I had three phantom sacs on my hands.

Haha that's funny. But interesting. I'm still new and learning, noticed it seemed to be a trend almost only the bred females produced sacs. It would be very interesting if courtship/male presence was an effective trigger.

It is also interesting how breeding does not guarantee sac production either, she can molt out not long after.

That's an excellent observation re: black widows. It's yet another thing that makes me wonder how the sperm survive for so long, especially if they are in a sealed, enclosed section in the body with no supplement in any form? Do the males also deposit proteins for the sperm during mating? Black widow males have huge bulbous pedipalps.. sperm+ proteins?
 

cold blood

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sperm is stored until its used, or lost with the next molt....it carries no expiration date.
 

TarantulaArvind

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A couple of weeks back, I saw in a thread that some species of T have been observed to be able to produce parthenogenic egg sacs(ie producing viable offsprings /eggs without sexual fertilisation. A member in that post had mentioned that it's been recorded in TKG.. how true it is, I dunno, wasn't able to verify.. @mconnachan??

It is possible for them to produce phantom sacs, meaning the eggs aren't fertilized, and will never develop. It happened to me with a large WC female Hysterocrates sp. Cameroon, she molted twice during my care and eventually just produced an egg sac, I had never bred her.

I was very surprised to find her with a sac, but I knew it was impossible for it to carry viable offspring. I'm not sure how often this happens but it's definitely interesting, here's the pics I got of her and the egg sac.
 

boina

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A couple of weeks back, I saw in a thread that some species of T have been observed to be able to produce parthenogenic egg sacs(ie producing viable offsprings /eggs without sexual fertilisation. A member in that post had mentioned that it's been recorded in TKG.. how true it is, I dunno, wasn't able to verify.. @mconnachan??
A thread on here? I somehow doubt that. Parthenogenesis has not ever been observed in tarantulas and it's certainly not in the TKG.

Now, double clutching is possible, meaning not all sperm get's released for the first sac and the female can make another one without being inseminated again by a male. The sac is still fertilized as usual with 'leftover' sperm.

Some tarantula species (I forgot which one it was) don't have a spermatheca and store sperm inside their bodies, so if they molt the sperm is still inside of them. Those few tarantulas can produce a fertile egg sac after a molt without being inseminated again. The eggs are still fertilized from a previous pairing with a male, though.

Maybe that person talking about parthenogenesis misunderstood.
 

mconnachan

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A couple of weeks back, I saw in a thread that some species of T have been observed to be able to produce parthenogenic egg sacs(ie producing viable offsprings /eggs without sexual fertilisation. A member in that post had mentioned that it's been recorded in TKG.. how true it is, I dunno, wasn't able to verify
That's correct I was reading it in the TKG, I'll have a proper read of the text tonight and post what information I find, but yes they can and have reproduced asexually.
 

mconnachan

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That's correct I was reading it in the TKG, I'll have a proper read of the text tonight and post what information I find, but yes they can and have reproduced asexually.
I have just found the passages that I read, I must have read in between the lines on pages 295-296 regarding parthenogenesis, it has been documented in insects and other inverts. So I must retract my statement "yes they can and have". Although having retracted my statement, I'm sure under certain circumstances asexual egg sacs have been produced as in other animals, such as the Komodo Dragon.
 

boina

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I have just found the passages that I read, I must have read in between the lines on pages 295-296 regarding parthenogenesis, it has been documented in insects and other inverts. So I must retract my statement "yes they can and have". Although having retracted my statement, I'm sure under certain circumstances asexual egg sacs have been produced as in other animals, such as the Komodo Dragon.
There are lizards that reproduce asexually, but Varanus?? Really? You have a source?
 

mconnachan

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There are lizards that reproduce asexually, but Varanus?? Really? You have a source?
Not sure about monitor lizards but yeah Komodo Dragons for sure, google it and you'll get the same info I referenced from.
 

boina

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Not sure about monitor lizards but yeah Komodo Dragons for sure, google it and you'll get the same info I referenced from.
A Komodo dragon is a monitor lizard ;). And yes, I found it and I'm amazed.
 
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