Dolomedes phantom sac?

[PidderPeets]

My boyfriend has had a wild caught female Dolomedes sp. (suspect D. tenebrosus) for quite a few months now (I can't remember exactly, but I wanna say about 4 or 5 months). She molted quite early on and has been a beast with eating ever since.

The other day he mentioned that she was in her hide, which she has never done before. Today is the first time I've been at his house since he told me that, and I noticed that she's carrying an eggsac!

As far as we're aware, she's had no access to any males, and she has molted in the time he's had her.

So I'd just like some confirmation that Dolomedes are or are not capable of laying phantom sacs. I know tarantulas are capable of it, but I'm a bit uneducated when it comes to true spiders. The last thing I want is to just assume it's a phantom sac if it turns out they can't produce phantom sacs.

I will provide pictures shortly, I just need to charge my phone up a bit

 

[chanda]

Pretty much all spiders will lay egg sacs regardless of whether they're fertilized or not. I've had Trechalea gertschi, Latrodectus hesperus, Latrodectus geometricus, various Salticidae, Peucetia viridans, assorted Sparassidae and Lycosidae, Selenops sp., several different orb weavers, and a variety of others all lay egg sacs despite having never mated. Of course, none of the egg sacs hatched - but many of the spiders still tended to/guarded the sacs, the same as if they were fertile. The Trechalea and Lycosidae even carried the sacs around with them for a few weeks before eventually abandoning them.

 

[PidderPeets]

Pretty much all spiders will lay egg sacs regardless of whether they're fertilized or not. I've had Trechalea gertschi, Latrodectus hesperus, Latrodectus geometricus, various Salticidae, Peucetia viridans, assorted Sparassidae and Lycosidae, Selenops sp., several different orb weavers, and a variety of others all lay egg sacs despite having never mated. Of course, none of the egg sacs hatched - but many of the spiders still tended to/guarded the sacs, the same as if they were fertile. The Trechalea and Lycosidae even carried the sacs around with them for a few weeks before eventually abandoning them.

Thanks for the info! I suspected that was the case, but I'd much rather make sure. Nothing good comes from making assumptions. And just to clarify, there's no way for her to have retained some sperm from before she molted, correct?

 

[chanda]

Thanks for the info! I suspected that was the case, but I'd much rather make sure. Nothing good comes from making assumptions. And just to clarify, there's no way for her to have retained some sperm from before she molted, correct?

Correct. When she shed her skin, she also shed the linings of her spermathecae.

 

[PidderPeets]

Correct. When she shed her skin, she also shed the linings of her spermathecae.

Thank you, I just wanted to make sure I'll guess we'll just let her walk around with it until she abandons it

 

[Hokey]

Pretty much all spiders will lay egg sacs regardless of whether they're fertilized or not. I've had Trechalea gertschi, Latrodectus hesperus, Latrodectus geometricus, various Salticidae, Peucetia viridans, assorted Sparassidae and Lycosidae, Selenops sp., several different orb weavers, and a variety of others all lay egg sacs despite having never mated. Of course, none of the egg sacs hatched - but many of the spiders still tended to/guarded the sacs, the same as if they were fertile. The Trechalea and Lycosidae even carried the sacs around with them for a few weeks before eventually abandoning them.

Do you know how long after fertilization a female will make an egg sac? I caught a female about 4 weeks ago and she is currently creating an egg sac. I have videos if that helps. Pretty cool to watch up close.

 

[chanda]

Do you know how long after fertilization a female will make an egg sac? I caught a female about 4 weeks ago and she is currently creating an egg sac. I have videos if that helps. Pretty cool to watch up close.

I'm sure it varies from one species to another, but I've had wild caught black widows produce up to 8 or 9 fertile sacs over the course of a year. I haven't noticed that any of my spiders create their egg sacs at regular intervals - they just do it when they're ready. Many spiders are able to retain sperm after even a single mating and lay multiple sacs when conditions are right.