parthenogenic black widow?

[fortysixandtwo]

Hey all. I'm new to the forum but I have been in the hobby of collecting and raising insects & arachnids since i was a wee lad. anyway, I have raised black widows for many years. Of all of the specimens I have kept in the past, none ever tried to lay eggs. They have all been kept in basicaly the same container, in my room which I know would not allow for a male to penetrate. I came home this morning after being gone for a few days and to my surprise, my present spider has created an egg sack, and within I can see a small dot. I was not aware that black widows were capable of parthenogenic reproduction. Since no other spider i have ever kept has done this, I am a bit surprised. I was just wondeirng if anyone else has experienced this with latrodectus mactans and if indeed it will truely become a full egg sack of spiderlings. Take care,

-Nick

 

[Devon]

I've never heard of that and that would be a big discovery so definately keep an eye on them. If it is the case they should all be female I'd guess.

Devon

 

[lucanidae]

If it was a wild caught spider than it could have already been fertalized, as is often the case. If not, it is an unfertalized eggsac, which does happen in spiders. I do not believe parthenogenesis is found in spiders.

 

[fortysixandtwo]

It has been in a jar for two years, i caught it when it was very young, so i really do not believe it ever mated. I obtained her when she was less than a month old. it has never done this until now. I will keep an eye on it and see what happens.

 

[Crotalus]

It has been in a jar for two years, i caught it when it was very young, so i really do not believe it ever mated. I obtained her when she was less than a month old. it has never done this until now. I will keep an eye on it and see what happens.

As Lucanidae writes, its most likely a infertile eggsack

 

[ScorpDemon]

It has been in a jar for two years, i caught it when it was very young, so i really do not believe it ever mated. I obtained her when she was less than a month old. it has never done this until now. I will keep an eye on it and see what happens.

2 years is a long time for a L. mactans. She probably won't be with you much longer. But yes they will lay unfertile sacs as others have mentioned.

 

[fortysixandtwo]

I had a black widow that lived to be about 3 years and 6 some months old. didnt have exact count but it was well over 3 years.

 

[NRF]

If it was a wild caught spider than it could have already been fertalized, as is often the case. If not, it is an unfertalized eggsac, which does happen in spiders. I do not believe parthenogenesis is found in spiders.

There are in facts spiders which are proved to be parthenogenetic, for example Theotima minutissimus (Ochyroceratidae.). Triaeris stenaspis (Oonopidae) is also believed to be parthenogenetic. These two species (at least the first one) apparently have no males at all. But this is surely not the case in Latrodectus. I have had an Agelena labyrinthica reared from juv. which layed a sac with unfertilised eggs.

 

[lucanidae]

Cool! Is this caused by wolbachia?

 

[NRF]

May be, may be not. Wolbachia has been found in spiders, but I don't think it has been studied in these two species. I don't think it si known why parthenogenesis has evolved in spiders, and why it is so uncommon compared to that in mites and ticks.

 

[The Snark]

In a study at the McCurdy nature center around 1970, isolated Latrodectus, usually towards the end of their lifespan, occasionally tended to develop a psuedo-parthenegenisis. Most egg sacks were sterile but a few produced young, most of which died within a few days. No progeny survived more than a month.
The conclusion that was reached, which supported the hypothesis that it extremely difficult for parthenegenic traits to develop in the Latro, was an inherent gene imbalance or weakness which naturally inhibited X chromosome development. Due to the deaths of the progeny, it was strongly suspected that there was a genetic weakness stemming from the parthenegenisis and thus the pseudo label was attached.

 

[tom]

latrodectus

Latrodectus tredecimguttatus have also produced egg sacs that are also infertile.As evidenced in my collection from captive raised spiders with no male interactions for mating. they produced after heavy feeding in the spring.