Phantom egg sac.

[Alexander Ramsey]

My P formosa has made a phantom egg sac recently and unfortunately my male is yet to have his maturing cast. I asked around about this and got the impression that phantom egg sacs are not that common but obviously a definate sign that the female is ready.
Today while doing the rounds my P Irminia has done the same thing.

Obviously I'm now searching for a MM but wondered if anyone else has seen this and how common it is (or isn't)?

Is there a reason why they do this apart from the obvious? Could the conditions be slightly wrong? or just right?

[Colin D Wilson]

How long have you had the spiders? i've known them to hold off sac making for absolute ages untill things were just right ... just a possibility.

regarding phantom sacs, there's lots of speculation as to why, i'm not sure if it can be pinpointed to one reason to be honest. Using up waste/excess materials seems to be quite a good theory, checking the system out to see if egg production is possible is one of the more dubious ones in my opinion but who knows exactly.

I've had Grammostola porteri drop egg sacs and leave them lying around (no where near a male as they've been grown on by myself) and also Avicularia sp "avicularia/Guyana" that i'd had from sling so no chance of meeting a male there either.

[Alexander Ramsey]

I've had the irminia from a juvenile so there's no possibility of fertility. The formosa I bought as a breeding pair and both have cast in my posession and the male I'm pretty certain is one cast away from maturity. He's definately not been near the female since she cast.
Also the female has now eaten the egg sac and gone on a rampage trashing all the webbing she'd done and tossing balls of substrate around.
I'm hoping to couple up the irminia soon, should I wait till she's eaten the egg sac or just try him in and see what the reaction is?
Any advice welcome.

[Tom Patterson]

Hi Alexander , how sure are you, your P. formosa is not a P. fasciata ?

Later, Tom

[Alexander Ramsey]

Honestly Tom, not that sure. They were bought as a breeding pair of pokey's and after a little Id help on line that was the common answer.
I'm happy to throw a few pics on if you want a shot at it?