Female Cobweb Weaver?

[JumpSpidersInc]

I have looked & looked too, Phil. Never met a spider that resisted an ID so hard! LOL.

The "owner" of the spiders wants to raise/keep them. Also in the same bathroom are a few more that are too high to reach. Hmmm.. Arboreal cobweb weavers??? :O

The fact that the male is allowed so near, even with abundant food to be had, is also most curious, IMHO.

I am wondering if this isn't a color "morph" of a spider we do know....... ????? Totally at a loss.

[Phil]

Most Theridiids are arboreal in a sense. I find them up in the wood frame of my garage all the time with Agelenids. I actually just found a really cool web, where a giant house spider moved in right above a mature female Steatoda grossa. If you know S. grossa, you know they always have a sheet type run path to their hide. The giant house spider made its funnel right on top of the S. grossa sheet, so they both path down the same spot, but avoid each other completely. It's one of the weirdest things I've seen. It just goes to show how tolerant spiders can be. I find many species within inch proximity of each other. I live on the forest edge, and food is abundant around my home, so spiders have no desire to risk fighting another spider, and enjoy eating the bugs and sharing space. This obviously isn't black and white, a lot of spiders eventually get eaten by the bigger/faster/dominate spider. Often you are viewing their tolerance, before it hits the point of one being eaten by the other. It's all about opportunity!

Don't rule out the male possibly being in the wrong web, this happens, and sometimes they cannot leave, as navigating the cobweb to escape alerts the owner to their location. They will hide (like this male has) under something and try to escape safely.

[JumpSpidersInc]

^ This whole post makes perfect sense!

A Teg and a Steatoda so close together is amazing!

[Mandy]

The female is almost definitely Megalepthyphantes nebulosus (previously Lepthyphantes nebulosus), a type of "sheetweb weaver" in the family Linyphiidae. It's a synanthropic species that's been introduced to North America from Europe (where most of our imports come from). It's been established here for a while now and is found in quite a few states, including Utah. A cobweb spider (family Theridiidae) wouldn't build a web that is so sheet-like, so that is typically a good indicator to think about additional options for ID. There are also some very prominent spines on this female's legs, which is not something typical of cobweb spiders, but is common in linyphiids (family Linyphiidae).

M. nebulosus usually lives near the ground somewhere, but I read that the females might move to a higher spot to lay eggs... maybe that's what she's doing that far off the ground.

As for the male spider in the other thread, it's definitely not the same species (male M. nebulosus look practically the same as the female but with big palps and a skinnier abdomen). That one really is a cobweb spider in the genus Steatoda. The palp would have to be seen under a microscope to tell which species in this case. It's not a male I have personally seen before (I've seen others whose abdominal pattern is the same, but their palps are much larger).

Looks like their webs are totally separate, they're just close to one another.

[JumpSpidersInc]

Mandy, thank you SO much for this. I think that with the male Steatoda being in such close proximity made ID of both very confusing.

Looking at the pics more closely, I agree that the webs are not touching, otherwise the female would be all over the poor Steatoda.

[Mandy]

No problem! It's our first Megalepthyphantes nebulosus, too, so was exciting to move it to a new archive.